Multifetal pregnancy reduction: evaluation of fetal growth in the remaining twins

OBJECTIVE: Our purpose was to study fetal growth after reduction of high-order multiple gestations to twins. STUDY DESIGN: Birth weight and gestational age data were collected for 236 triplet and greater multiple pregnancies reduced to twins (113 triplets, 89 quadruplets, and 34 quintuplets or above) and was compared with those of a control group of unreduced twins. RESULTS: Rates of intrauterine growth restriction per pregnancy were significantly different between the nonreduced and all categories of reduced multifetal pregnancies. The incidence of intrauterine growth restriction was 19.4% in the nonreduced twins, 36.3% in pregnancies reduced from triplets, 41.6% in pregnancies reduced from quadruplets, and 50% from higher-order multiple gestations. There was a statistically significant trend toward increasing frequency of intrauterine growth restriction with increasing starting fetal number (p = 0.04). The increase in intrauterine growth restriction was primarily accounted for by twin pairs with only one growth-restricted newborn. CONCLUSION: Multifetal pregnancy reduction does not reduce the incidence of intrauterine growth restriction in the remaining fetuses to that of nonreduced twins.     

Effects of fetal number and multifetal reduction on length of in vitro fertilization pregnancies

OBJECTIVE: To determine the effects of multifetal reduction and other variables on the duration of gestation of in vitro fertilization (IVF) pregnancies. METHODS: All 274 IVF pregnancies from the inception of the Women and Infants' Hospital IVF Program on May 26, 1988, until December 31, 1993, were evaluated. RESULTS: Spontaneous reduction occurred in ten pregnancies, and multifetal reduction was elected in 28 multiple gestations. Among 260 pregnancies that remained viable beyond 20 weeks, 162 singletons (37.9 +/- 0.29 weeks; mean +/- standard error) had a longer mean gestation than did 64 twins (34.6 +/- 0.61 weeks), 25 pregnancies reduced to twins (33.4 +/- 1.0 weeks), or nine triplets (29.7 +/- 1.9 weeks). Triplets delivered 4.9 weeks earlier than nonreduced twins (P < .05) and 3.7 weeks before twins resulting from multifetal pregnancy reduction (P < .05). Regression analysis showed that at the 8-week ultrasound, each viable fetus could be expected to reduce the duration of the gestation by about 3.6 weeks, and each fetus reduced medically or as a result of natural causes could be expected to prolong the gestation by approximately 3.0 weeks. Only 14% of triplet pregnancies underwent spontaneous multifetal reduction. CONCLUSION: Multifetal reduction of pregnancies with three or more fetuses was beneficial and increased the duration of gestation.     

Complications of vertebral metastasis surgery

The objective of the study was to evaluate the crown-rump length (CRL) in high-order multifetal pregnancies (three or more fetuses). The records of patients who underwent multifetal pregnancy reduction were reviewed. The following parameters were defined: the mean CRL (CRLMEAN) and the difference between the largest and smallest CRL (CRLRANGE) for each pregnancy. CRLMEAN was plotted versus gestational age (GA) and the line of best fit was derived. The residual for each CRL (CRLRES) was calculated by subtracting the value predicted by the regression line from the individual CRL (CRLIND). Regression lines for single-tons with confirmed GA from four previously reported studies were used for comparison. A total of 82 patients were included (29 triplets, 38 quadruplets and 15 quintuplets; mean GA 10.7 +/- 0.78 weeks). CRLMEAN correlated with GA (CRLMEAN = 38.88 - 8.78(GA) + 0.82(GA)2; R = 0.83; R2 = 0.70). This second-degree polynomial remained within the range for singletons. No significant differences in maternal age, GA and CRLMEAN were noted between the patients with different numbers of fetuses. The median CRLRANGE was largest in quintuplets, followed by quadruplets and triplets. The CRLRANGE correlated poorly with GA. The mean CRL in multifetal pregnancies increases with GA similarly to that in singletons. The variability of individual measurements increases with the number of fetuses and CRLs are lower in quintuplets.     

Oocyte donation to women of advanced reproductive age: pregnancy results and obstetrical outcomes in patients 45 years and older

We analysed the results of oocyte donation to women of advanced reproductive age (> or = 45 years old) and followed their pregnancies through to delivery in order to assess obstetrical outcomes. Patients (n = 162) aged 45-59 years (mean +/- SD; 47.3 +/- 3.4 years) underwent 218 consecutive attempts to achieve pregnancy. Oocytes (16.2 +/- 7.2 per retrieval) were provided by donors < or = 35 years old. Cleaving embryos (8.2 +/- 4.8 zygotes/couple) were transferred transcervically (4.5 +/- 1.1 per embryo transfer) to recipients prescribed oral micronized oestradiol and intramuscular progesterone. Following oocyte aspiration there were six instances of non-fertilization (2.8%) and 212 embryo transfers. A total of 103 pregnancies was established for an overall pregnancy rate (PR) of 48.6%, which included 17 preclinical pregnancies, 12 spontaneous abortions, and 74 delivered pregnancies (clinical PR 40.6%; delivered PR 34.9%). Multiple gestations were frequent (n = 29; 39.2% of pregnancies) and included 20 twins, seven triplets, and two quadruplets. Two of the triplet and both of the quadruplet pregnancies underwent selective reduction to twins. Antenatal complications occurred in 28 women (37.8% of deliveries) and included preterm labour (n = 9), gestational hypertension (n = 8), gestational diabetes (n = 6), carpel tunnel syndrome (n = 2), pre-eclampsia (n = 2), HELLP syndrome (n = 2), and fetal growth retardation (n = 2). 48 (64.8%) deliveries were by Caesarean section. The gestational age at delivery for singletons was 38.3 +/- 1.3 weeks (range 35-41 weeks), with birth weight 3218 +/- 513 g (range 1870-4775 g); twins 35.9 +/- 2.0 weeks (range 32-39 weeks), birth weight 2558 +/- 497 g (range 1700-3450 g); and triplets 33.5 +/- 0.7 weeks (range 32-34 weeks), birth weight 1775 +/- 190 g (range 1550-2100 g). Neonatal complications (4.6% of babies born) included growth retardation (n = 2), trisomy 21 (n = 1), ventricular septal defect (n = 1), and small bowel obstruction (n = 1). There were no maternal or neonatal deaths. We conclude that oocyte donation to women of advanced reproductive age is highly successful in establishing pregnancy. However, despite careful antenatal screening, obstetrical complications are common, often secondary to multiple gestation.     

Prevalence of cerebral palsy in twins, triplets and quadruplets

BACKGROUND: Twins and triplets are at higher risk of cerebral palsy than singletons. This study investigated the degree of risk for cerebral palsy in twins, triplets and quadruplets, and identified factors associated with the increased risk. METHODS: The subjects were recruited from the Kinki University Twin and Higher Order Multiple Births Registry. RESULTS: The subjects were 705 twins pairs (1410 twins), 96 sets of triplets (287 triplets excluding one infant death), and 7 sets of quadruplets (27 quadruplets excluding one infant death), who were born after 1977. The prevalence of cerebral palsy was 0.9% among 1410 twins, 3.1% among 287 triplets, and 11.1% among 27 quadruplets. Furthermore, the risks of producing at least one child with cerebral palsy were 1.5%, 8.0%, 42.9% in twin, triplet, quadruplet pregnancies, respectively. After adjusting for each associated factor using logistic regression, the risk of cerebral palsy was significantly associated with decrease in gestational age and asphyxia. The odds ratio indicated that infants whose gestational age was < 32 weeks were 20 times more likely to develop cerebral palsy than infants whose gestational age was > or = 36 weeks. CONCLUSIONS: The prevalence of cerebral palsy in triplets and quadruplets was higher than that in twins. Lower gestational age was associated with a greater risk of cerebral palsy.     

A comparison of sonographic growth curves of triplet and twin fetuses

Sonographic growth curves of 47 normal triplet pregnancies were compared with those of 71 uncomplicated twin gestations. Starting from the 25th week, the biparietal diameter in triplets was found to lag progressively compared with that of twins, reaching a mean difference of 2 weeks at 36 weeks gestation. Similarly, a significant difference was found between the femur length and head to abdomen circumference ratio growth curves of triplets and twins. It is concluded that as pregnancy continues from the 25th to the 36th gestational week, there is a significant delay in the growth patterns of normal triplet pregnancies compared with twin gestations.     

Atypical presentation of preeclampsia in high-order multifetal gestations

OBJECTIVE: To describe our experience with preeclampsia in high-order multifetal gestations. METHODS: Records for all triplet and quadruplet pregnancies delivered after 24 weeks' gestation from January 1988 through June 1994 were reviewed. All patients were treated with bed rest from 20 weeks' gestation onward and received corticosteroids weekly beginning at 24 weeks. Tocolytics were used as needed. RESULTS: Twenty-one triplet and eight quadruplet pregnancies were studied. The mean gestational age at delivery was 32.3 and 27.9 weeks, and mean birth weights were 1547 and 1028 g, respectively. Seventeen of 29 patients developed preeclampsia, 14 of the 21 triplet mothers and three of the eight quadruplet mothers. Among 16 patients who were delivered for preeclampsia, only eight had blood pressure (BP) elevation before delivery, whereas ten had epigastric pain, visual disturbances and/or headache; nine had elevated liver enzyme levels; and seven had low platelet counts. Only three patients had proteinuria, and only six had edema. Five women developed the syndrome of hemolysis, elevated liver enzymes, and low platelets postpartum, all of whom had normal BP before delivery. Two patients developed preeclampsia after delivery. A total of 95 infants were delivered, all by cesarean, of whom 93 (98%) survived. CONCLUSION: Preeclampsia is common in high-order multifetal gestations and often presents in an atypical manner. Hypertension is not always the presenting sign, and symptoms consistent with severe preeclampsia and abnormal laboratory values predominate.     

Limiting multiple pregnancy in in vitro fertilization/embryo transfer (IVF-ET) cycles

PURPOSE: Our purpose was to assess how the number of embryos transferred can be adjusted to limit multiple gestations. METHODS: A retrospective analysis of 535 consecutive embryo transfers for the years 1991-1993 was conducted. RESULTS: Fewer than three embryos were associated with a low pregnancy rate. Pregnancy rates were highest in women less than 35 when four or more embryos were transferred. With four or more embryos, multiple gestation pregnancy correlated with the number of high-quality embryos transferred. The risk of triplets and quadruplets was greatest for women less than 40. CONCLUSIONS: Multiple-embryo transfer carries a risk of plural gestation. The risk of multiple pregnancy cannot be eliminated without decreasing the pregnancy rate. The risk of high-order multiple pregnancy was best correlated with the number of good-quality embryos transferred. While all are at risk, patients younger than 40 were at highest risk.     

Triplet and quadruplet pregnancy: management and perinatal outcome

The frequency of multiple pregnancies with more than two fetuses has increased considerably since the introduction of methods of ovulation induction, in vitro fertilization, and embryo transfer. We have analyzed the evolution, complications, delivery and perinatal outcome of 23 triplet and 3 quadruplet pregnancies occurred during a four-year period in one medical center. The most frequent complication was preterm labor (62%). The mean gestational age at delivery was 32.5 weeks for the quadruplets and 31.5 weeks for the triplets and the mean birth weight was 1461 and 1526 for quadruplets and triplets, respectively. Perinatal mortality for the whole group was 148/1000.     

How accurate is fetal biometry in the assessment of fetal age?

OBJECTIVE: The purpose of the study was to assess the accuracy of fetal biometry in the midtrimester of pregnancy in the assignment of fetal age. STUDY DESIGN: A total of 152 singleton, 67 twin, and 19 triplet gestations resulting from in vitro fertilization with ultrasonographic fetal biometry from 14 to 22 weeks made up the study population. A gestational age prediction equation was derived from singletons with the use of stepwise linear regression. This equation was compared with 38 previously published equations and then applied to the twin and triplet populations. RESULTS: Head circumference was the best predictor of gestational age (random error [SD] 3.77 days). Addition of abdominal circumference and femur length to head circumference improved the accuracy of the dating equation (random error 3.35 days). Most dating formulas had systematic errors of <1 week. The systematic error was -0.32 day for averaging the singleton-based predictions for twins and -1.26 days for triplets. CONCLUSIONS: Gestational age assessment with the use of fetal biometry from 14 to 22 weeks is accurate for singleton, twin, and triplet gestations.     

Risks of subsequent pregnancies on mother and newborn in female heart transplant recipients

BACKGROUND: Female heart transplant recipients are able to carry pregnancies successfully. This study evaluates the effect of subsequent pregnancies on newborn and maternal outcomes and graft survival. METHODS: Subjects were identified through a previously reported multicenter study, case reports from literature review, and recipients entered in the National Transplantation Pregnancy Registry. A retrospective analysis was completed of 35 heart transplant recipients with first pregnancies (FP) and 12 who had one or two additional pregnancies (P>1). Newborns were assessed for gestational age, neonatal birth weight, and complications. Maternal data included pregnancy outcome, peripartum complications, including infection and rejection, current graft function, and recipient survival. RESULTS: Forty-seven pregnancies (35 FP and 12 P>1) from 35 heart transplant recipients were studied. FP outcomes included 26 live births (one set of twins), four miscarriages, and six therapeutic abortions, whereas P>1 outcomes included 11 live births (one set of twins), and two miscarriages. There was no significant difference between mean birth weights (2353+/-986 gm vs 2588+/-521 g, P>1 vs FP; mean+/-SD; p=NS) or prematurity incidence (<37 weeks; 50% vs 40%; p=NS) for the live-born infants. Compared with the FP group, there was a trend toward increased neonatal complications in P>1 (40% vs 12%; p=NS). Complications were significantly more common in premature newborns compared with full-term newborns (33% vs 5%; p < 0.05). No structural malformations were identified in the live-born infants. Maternal complication rates were the same in both groups (40%). Of 28 recipients available for follow-up, the maternal survival rate was 75% for the FP group and 89% for the P> group. Mean rejection rate per year was slightly increased after pregnancy in the P>1 group. Surviving recipients had similar graft function by echocardiographic left ventricular ejection fraction. CONCLUSIONS: Post-heart transplantation pregnancies often have successful outcomes, but there is a high incidence of prematurity and low birth weight. Subsequent pregnancies do not seem to significantly increase the incidence of complications in either the newborn or mother or increase graft rejection or failure. Larger studies of posttransplantation pregnancies may provide more definitive information.     

Cerebellar growth in normal and growth-restricted fetuses of multiple gestations

OBJECTIVE: Our purpose was to evaluate growth of the cerebellum in growth-restricted fetuses of twin and triplet gestations versus growth in normal in utero sibling(s) and in singleton gestations. STUDY DESIGN: An ultrasonographic study was conducted in a population of pregnant women with twin and triplet gestations. The control group was either the normal in utero sibling(s) when one fetus was growth restricted or normal twin and singleton pregnancies. Standard biometric measurements were obtained on all fetuses throughout pregnancy, including the transverse cerebellar diameter. However, only the last measurement was used for the analysis. Statistical analyses were conducted comparing growth of the transverse cerebellar diameter among the growth-restricted fetuses versus growth in the normal in utero fetal sibling(s) or other normal twin and singleton gestations. RESULTS: Pregnancies were categorized on the basis of the growth status of women with twin and triplet gestations: Group 1 (151) contained women with two fetuses appropriately grown for gestational age; group 2 (52) had one appropriately grown fetus and one with intrauterine growth restriction; group 3 (19) had two fetuses with intrauterine growth restriction. In addition, there were 30 triplet gestations (group 4), five of which had growth-restricted fetuses, and group 5 contained 1405 singleton pregnancies. In all five groups there was a statistically significant relationship between transverse cerebellar diameter and gestational age (p < 0.0001). There was also no significant difference between growth of the transverse cerebellar diameter in the appropriately grown and growth-restricted siblings and among normal singleton and twin pregnancy groups. In most cases of growth-restricted fetuses, except for the transverse cerebellar diameter measurements, all other biometric parameters were < 10th percentile. CONCLUSION: These data confirm the relative preservation of normal cerebellar growth in growth-restricted fetuses and a similar rate of growth in singleton and multifetal gestations. The transverse cerebellar diameter therefore represents an independent biometric parameter that can be used in both singleton and multifetal pregnancies to assess normal and deviant fetal growth.     

Selective termination and elective reduction in twin pregnancies: 10 years experience at a single centre

Selective termination is employed in multifetal pregnancies, in the presence of an abnormal fetus, in order to improve the prognosis of the normal fetuses. The term elective reduction is used to describe reduction in twin pregnancies for maternal medical conditions, psychological, or socioeconomic reasons. The purpose of this study was to evaluate the factors that influence outcome in such pregnancies. Eighty-two twin pregnancies underwent selective termination (n = 59) or elective reduction (n = 23) over a 10-year period. Early procedures, performed < or = 14 weeks (n = 31), had a pregnancy loss of 9.7% and a mean procedure-to-loss interval of 4.1 +/- 2.8 weeks; mean birthweight was 3299 +/- 395 g in survivors, with a mean gestational age at delivery of 38.4 +/- 2.3 weeks. In comparison, procedures performed > 14 weeks (n = 51) had a pregnancy loss of 7.8%, with a procedure-to-loss interval of 1.2 +/- 0.6 weeks. Mean birthweight was 2577 +/- 999 g, with a mean gestational age at delivery of 35.7 +/- 5 weeks. In conclusion, outcomes were more favourable among patients who underwent a first trimester procedure. The slight increase in pregnancy loss may be attributed to a higher than expected rate of spontaneous abortions in the first trimester, as manifested by the higher procedure-to-loss interval after a first trimester procedure. These facts underscore the importance of early detection of fetal abnormalities in twin pregnancies by ultrasonography and chorionic villus sampling.     

Five-year follow-up after balloon pulmonary valvuloplasty

We hypothesized that gender and intrauterine growth retardation (IUGR) have greater effects than birth order on mortality and morbidity rates of very low birth weight (< 1501 gm) twins. Neonatal data were collected on 44 pairs of twins born alive between January 1984 and December 1987. Birth weight was 1018 +/- 289 gm and gestational age was 28.1 +/- 2.5 weeks. The male/female ratio was 46:42; 24 infants had IUGR, and 64 were appropriate in size for gestational age. Of the 88 infants, 61 (69%) survived. Birth order had no effect on outcome. Female twin pairs had a longer gestation than either male twin pairs or twins with discordant sex (29.2 +/- 2.5 weeks vs 27.4 +/- 2.0 weeks and 27 +/- 3 weeks, respectively; p < 0.002). They also had a lower mortality rate (14% vs 47% and 25%; p < 0.001) and a lower incidence of bronchopulmonary dysplasia (22% vs 57% and 50%; p < 0.02). Infants with IUGR had an increased mortality rate (50% vs 23%; p < 0.02) and an increased sepsis rate (61% vs 25%; p < 0.02) compared with infants with appropriate size for gestational age who were matched for gestational age. Multiple logistic regression analysis to assess the independent effects of gestational age, gender, and IUGR on mortality rate, bronchopulmonary dysplasia, and intraventricular hemorrhage revealed that gestational age was the most significant contributor to all three outcome variables; IUGR contributed to an increased mortality rate, and male gender contributed to the occurrence of bronchopulmonary dysplasia.     

National Transplantation Pregnancy Registry: analysis of pregnancy outcomes in female liver transplant recipients

Outcomes from 48 pregnancies in 34 female liver transplant recipients were analyzed. Data were collected via interviews, questionnaires, and hospital records. All recipients were treated with cyclosporine-based immunosuppression except 2 patients treated with FK506 and 2 treated with no immunosuppression. The age at conception was 26.1 +/- 5.9 years (mean +/- SD) with a transplant interval (time from transplantation to conception) of 2.9 +/- 2.5 years. There were 49 outcomes (1 set of twins): miscarriage 9 (18%), therapeutic abortion 4 (8%), and live birth 36 (74%). No stillbirths or ectopic pregnancies were reported. Of the 36 live births, the gestational age was 36.9 +/- 3.5 weeks, the birthweight was 2,604 +/- 698 grams, 39% were premature (< 37 weeks), and 31% had low birthweight (< 2,500 grams). No birth defects or neonatal deaths (< 28 days) were reported. The newborn complication rate was 17% (n = 6), 5% in premature infants. The incidence of drug-treated hypertension was 46%; pre-eclampsia 21%; infectious complications 26%; and Caesarean section 47%. Recipients with hypertension had a higher proportion of premature infants (71%) than normotensive patients (38%) (P = .04 by Fisher's exact test). Acute rejection was diagnosed in 6 pregnancies, 2 of which were ended by therapeutic abortion. Four recipients who continued their pregnancies were treated with increased immunosuppression for rejection, and all delivered livebirths. There were two grafts lost within 6 months of pregnancy. The only maternal death occurred in a patient who required retransplantation for recurrent C hepatitis 3 months afte therapeutic abortion and died 6 months later. The other recipient with graft loss was successfully retransplanted for chronic rejection 6 months after delivery. We draw the following conclusions: (1) female liver transplant recipients can safely undergo pregnancy, although there is a high rate of premature and low birthweight infants; (2) pregnancies in this population should be considered high-risk and require close monitoring of liver function; and (3) altered graft function during pregnancy should be thoroughly investigated.     

A microscopic analysis of cut-bevel versus pencil-point spinal needles

OBJECTIVE: Our purpose was to establish new nomograms for the birth weight of twins on the basis of accurate methods to validate gestational age. STUDY DESIGN: The medical records of 1632 consecutive twin gestations delivered between 1984 and 1996 were reviewed. Only pregnancies induced by ovulation induction techniques or that were measured ultrasonographically for crown-rump length during the first trimester were included. Excluded were those whose fetuses (one or both) were stillborn, or if the mother smoked, had a significant chronic illness, or was prescribed any regular medications. The study comprised 520 twin pregnancies at 28 to 41 gestational weeks at delivery. RESULTS: The median and 10th and 90th percentile birth weight curves were calculated for the studied twins and plotted against previously reported singleton nomograms. Fetuses of twin pregnancies were found to be growth restricted in comparison with previously reported singletons throughout the third trimester. This trend became more evident after the thirty-fourth to thirty-sixth weeks. CONCLUSIONS: We recommend these novel birth weight nomograms for clinical use in the management of twin pregnancies.     

Effects of embryo reduction from trichorionic triplets to twins

Sixty-six trichorionic triplet pregnancies reduced to twins were compared with 47 triplet pregnancies that were not reduced. The miscarriage rate was higher (7.6% compared with 2.6%) but the number delivering between 24 and 32 weeks was lower (8.2% compared with 24.0%). Since severe preterm delivery is associated with risks of neonatal death and severe handicap, embryo reduction of triplets to twins may not improve the chance of survival but may reduce the rate of handicap.     

"Appearing twin": undercounting of multiple gestations on early first trimester sonograms

An important role of first trimester sonography is to determine whether a pregnancy is a singleton, twin, or higher order multiple gestation. We assessed how frequently sonography at 5.0-5.9 weeks undercounts multiple gestations. We identified all pregnancies at our institution since 1988 in which (1) an initial sonogram obtained at 5.0-5.9 weeks demonstrated at least a singleton intrauterine pregnancy and (2) a subsequent sonogram at 6.0 weeks or beyond demonstrated a living multiple gestation. Twenty-four (11%) of 213 dichorionic twin gestations were initially undercounted as singletons, as were six (86%) of seven monochorionic twin gestations. Among 105 higher order multiples, 17 (16%) were undercounted initially. All but one of the undercounted cases were scanned transvaginally. Undercounting occurred in both natural and assisted conceptions, and it occurred more frequently on sonograms obtained at 5.0-5.4 weeks than at 5.5-5.9 weeks (P = 0.02, Fisher's exact test). Prognosis for undercounted multiple gestations was similar to that of correctly counted ones with respect to several measures of pregnancy outcome, including the likelihood that all fetuses would be delivered liveborn, gestational age at birth, and birth weight (P > 0.20, all comparisons). In conclusion, transvaginal sonography at 5.0-5.9 weeks frequently undercounts multiple gestations. Initially undercounted multiple gestations and those correctly counted have similar pregnancy outcomes.     

The effect of maternal smoking on birth weight in twin pregnancies

Information on 869 076 singletons and 17 566 twins, born during the period 1983-1991, was obtained from the Swedish Medical Birth Registry. Data on birth weight, gestational duration, vital status, and maternal smoking habits during pregnancy were analyzed in order to investigate whether twinning potentiates the effect of maternal smoking on birth weight and perinatal mortality. The individual birth weights were expressed as percentages of mean birth weight, where mean birth weights of singletons and twins were calculated separately. The birth weight reducing effect of maternal smoking was found to be of the same magnitude among twins and singletons weighing > 90% of mean birth weight. For infants weighing < 90% of mean birth weight, maternal smoking had a significantly stronger effect on birth weight among singletons than among twins. When gestational duration was taken into consideration, this difference was less pronounced. The effect of maternal smoking on gestational duration was stronger among singletons than twins. The smoking-related risk increase of perinatal death was of about the same magnitude among twins and singletons.     

Causes of perinatal mortality in twins

The author analyses perinatal mortality in 244 twin pregnancies. In 80% the twins' Apgare score at birth was 10 to 8 and neonatal mortality in this group 1.26%. The slightly asphyxial group (Apgar 7 to 4) comprised 62 (38.75%) twins and the neonatal mortality in this group was 14.51%. There were 20 (12.5%) severely asphyxial (Apgar 3 or less) twins, their neonatal mortality amounting to 80.0%. Out of 193 twins weighing at birth less than 2500 g, 45 (23.31%) died, while in the twins weighing more than 2500 g there was not a single death. The perinatal mortality of twins up to the 37th week of pregnancy amounted to 17.37% and from the 38th week of pregnancy to 1.22%. The mean duration of pregnancy in twins was 38.1 +/- 2 SD 6.3 weeks. The most frequent cause of death in twins has proved to be immaturity and asphyxia at birth, leading to the development of hyaline membranes (80.0%). Other causes were far less frequent. The author concludes that in the perinatal mortality of twins their vitality at birth (assessed by the Apgar score), birth weight, and the duration of pregnancy play an important role.