The association of parity with mortality outcomes among triplets

Prediction of perinatal mortality in triplet pregnancies

PURPOSE

To investigate predictors of perinatal mortality in triplet pregnancies.

METHODS

Retrospective cohort managed in a tertiary teaching hospital (1998-2012) including all pregnancies with tree live fetuses at the first ultrasound examination, performed after 11 weeks of gestation. Primary end-point was defined as the number of children alive at hospital discharge. Ordinal stepwise regression analysis examined the association with maternal age, parity, pregnancy chorionicity, gestational age at our first ultrasound evaluation, presence of maternal clinical, obstetrical and fetal complications and gestational age at delivery.

RESULTS

Sixty-seven triplet pregnancies were first seen at 18.5 ± 6.8 weeks, 33 (49.3 %) were trichorionic, obstetric complications occurred in 34 (50.7 %) and fetal complications were diagnosed in 17 (25.4 %). Perinatal mortality rate was 249 ‰ (95 % CI 189-317) and 138 (73 %) children were discharged alive from hospital (11 pregnancies with no survivors; single and double survival in ten cases each; all children alive in 36). Regression analysis showed that presence of fetal complications (OR 0.10, 95 % CI 0.03-0.36) and gestational age at delivery (OR 1.55, 95 % CI 1.31-1.85) are significant predictors of outcome (p < 0.001).

CONCLUSIONS

Perinatal mortality in non-selected triplet pregnancies is high and is related to the presence of fetal complications and gestational age at delivery.

Clinical features and short-term outcomes of triplet pregnancies in Japan

OBJECTIVE

To review clinical features and short-term outcomes of triplet pregnancies among Japanese women.

METHODS

A retrospective analysis was carried out among 320 Japanese women with triplet pregnancies (8 monochorionic, 75 dichorionic, and 150 trichorionic triplets; 87 with unknown placental chorionicity) who delivered at 22 gestational weeks or more between January 2005 and December 2008.

RESULTS

Delivery was by cesarean for 315 (98%) women. Gestational age at delivery was 32.3±2.8 weeks (mean±SD) and 33.2 weeks (median), and 97%, 61%, and 14% of women delivered at less than 37, less than 34, and less than 30 gestational weeks, respectively. For live-born infants, mean birth weight was 1762±437 g, 1608±396 g, and 1406±380 g for the heaviest, middle, and lightest triplet, respectively. Eighteen (5.6%) women experienced perinatal mortality (3 triplets for 1 woman, 2 triplets for 4 women, and 1 triplet for 13 women). Perinatal mortality was 25 deaths per 1000 deliveries, and decreased with increasing number of chorionic membranes (125, 44, and 20 per 1000 mono-, di-, and trichorionic triplet deliveries, respectively).

CONCLUSION

Short-term outcomes were good among triplet pregnancies in Japan. The data may be useful for counseling Japanese women with triplet pregnancies.

Effect of parity on gestational age at delivery in multiple gestation pregnancies

OBJECTIVE

To estimate the effect of parity on gestational age (GA) at birth in multifetal pregnancies.

STUDY DESIGN

Birth data from the public-access Matched Multiple Birth File produced by the National Center for Health Statistics from 1995 to 2000 were analyzed following IRB approval. GA, parity and demographic data were analyzed with parametric and nonparametric tests, including regression analysis, using SPSS.

RESULT

Data from women with twin (n=316,983), triplet (n=11,981), and quadruplet (n=766) pregnancies were analyzed. A significantly higher proportion of nulliparous versus parous women were Caucasian (twins: 82 versus 77%; triplets: 91 versus 87%) and had more than 15 years of education (twins: 39 versus 24%; triplets: 55 versus 39%; quadruplets: 53 versus 35%). Mean GA was 5.6 days longer for twins, 5.4 days longer for triplets and 6.8 days longer for quadruplets born to parous versus nulliparous women. Caucasian and African-American parous women pregnant with twins or triplets delivered their babies at a later GA than their nulliparous counterparts at each level of education. GA at delivery increased as a function of age of the mother in nulliparous and parous women of twins or triplets, and at every age level, parous women delivered their babies at a later GA. A higher proportion of nulliparous women delivered before 24 weeks (twins: 2.9 versus 1.2%; triplets: 5.9 versus 2.5%; quadruplets: 8.3 versus 2.6%). The percentage of twins born at or after 32 weeks was 84.9% for nullipara and 90.1% for parous women; for triplets, corresponding figures were 61.4 and 69.6%; and for quadruplets the figures were 33.2 and 44.2%. The percentage of births at or after 36 weeks for nulliparous and parous women pregnant with twins was 54.8 and 63.2%, respectively. The majority of the gain in GA was observed between women who had no previous births and those who had one previous birth. In regression analysis, the effect of parity remained after controlling for demographic and risk factors known to affect GA.

CONCLUSION

GA at delivery is significantly increased in parous women carrying a multifetal gestation after controlling for other factors that affect GA at birth.

The association between maternal characteristics and different types and levels of discordance in triplet pregnancies

OBJECTIVE

This study evaluated the association of maternal factors known to influence outcomes of triplets, different discordance levels (-25, 25.1-35, and )35%), and three types (according to the birth weight of the middle-sized triplet) of birth weight discordance in triplets.

METHODS

We used data collected by the Women's Health Division of Matria Healthcare, Inc. (Marietta, GA). We analyzed a cohort of 2706 triplet sets, to calculate the frequencies of different levels and types of birth weight discordance by maternal age, parity, weight, height, body mass index and weight gain at 24 weeks of gestation.

RESULTS

We found a positive association between maternal parity and birth weight discordance level but no clear association between the other maternal factors and the level of discordance as well as the type of discordance. However, a trend was seen whereby overweight women had a trend towards the low-skew (a set comprising one large and two small triplets) type of birth weight discordance and an opposite trend in underweight women.

CONCLUSIONS

These results corroborate previous findings that nulliparity is associated with aberrant growth in triplet pregnancies.

The association between small-for-gestational age triplet pregnancies and neonatal mortality: a novel approach to growth assessment in multiple gestations

It is customary to estimate the uteroplacental function in singletons by defining appropriateness of birth weight by gestational age. Such a measure, however, is not available for the entire multiple pregnancy set. We evaluate a new index, total triplet birth weight, expressed as multiples of the median (MOM) birth weight of singleton gestations. We categorized triplet sets as small-, appropriate-, and large-for-gestational age pregnancies (SGA, AGA, and LGA, respectively), defined as <1 SD, +/-1 SD, and >1 SD from the mean MOM birth weight of singleton gestations. We used the 1995-1998 US matched multiple dataset to evaluate this index and to explore the association between the three categories in terms of risk of neonatal mortality. The mean +/- SD MOM value was 2.3 +/- 0.4. There was an inverse correlation between mean MOM and gestational age. LGA pregnancy status was associated with multiparity, race (being white), and high social status (education). Maternal age did not influence MOM scores. Compared with the LGA pregnancy category, the risk for neonatal mortality was more than doubled in the AGA pregnancy group and more than 9-fold in the SGA pregnancy category. We propose that this new measure could be a useful proxy for the uteroplacental efficiency in a similar way that the SGA designation works for singleton infants.

Comparative study of perinatal outcome of dichorionic and trichorionic iatrogenic triplets

OBJECTIVE

The purpose of this study was to compare the perinatal outcome of dichorionic and trichorionic triplets who were conceived by assisted reproductive techniques.

STUDY DESIGN

In this retrospective study, the maternal, neonatal, and chorionicity data were collected from 106 sets of trichorionic triamniotic and 34 sets of dichorionic triamniotic triplet pregnancies who were conceived by assisted reproductive techniques between January 1986 and December 2000. Perinatal and neonatal data were evaluated in relation to chorionicity and intertriplet birth weight discordance.

RESULTS

The dichorionic triamniotic triplets have an 8-fold higher risk of perinatal death than trichorionic triamniotic gestations (odds ratio, 7.9; 95% CI, 4.4-14.0; P < .001). This is attributed to a higher risk of very low birth weight (P < .01), delivery at < 30 weeks of gestation (P < .001), and premature rupture of membrane (P < .001) in dichorionic triamniotic triplets compared with trichorionic triamniotic pregnancies. Twin-twin transfusion syndrome (odds ratio, 11.5; 95% CI, 4.8-27.7; P < .001), delivery at < 30 weeks of gestation (odds ratio, 40.5; 95% CI, 16.9-97; P < .01), premature rupture of membrane (odds ratio, 6.7; 95% CI, 3.8-11.9; P < .01), and nulliparity (odds ratio, 3.1; 95% CI, 1.6-6.1; P < .05) had independent effects on perinatal loss rate.

CONCLUSION

The dichorionic triplets have an 8 times higher perinatal mortality rate than trichorionic triamniotic pregnancies.

Perinatal outcome of spontaneously conceived triplet pregnancies in relation to chorionicity

OBJECTIVE

The purpose of this study was to determine the perinatal outcome of spontaneously conceived triplet pregnancies in relation to chorionicity.

STUDY DESIGN

In this retrospective study, maternal, neonatal, and chorionicity data were collected from 88 sets of triplet pregnancies that were delivered at >20 weeks of gestation from 3 tertiary referral centers in the United Kingdom. The data were collected between January 1986 and December 2000. There were 49 sets of trichorionic triamniotic triplet pregnancies and 39 sets of triplet pregnancies with a monochorionic pair (ie, dichorionic triamniotic triplets). The outcome of each pregnancy was assessed in relation to chorionicity.

RESULTS

The overall perinatal mortality rate was 151.5 per 1000 total births, with dichorionic triamniotic triplets having a 5.5-fold higher risk than trichorionic triamniotic gestations (odds ratio, 5.5; 95% CI, 2.5-12.2). The dichorionic triamniotic triplets have a higher risk of delivery at < 30 weeks of gestation (odds ratio, 4.6; 95% CI, 1.6-11.8; P < .05) and birth weight of < 1000 g (odds ratio, 53.6; 95% CI, 17.5-164; P < .05) than those of trichorionic triamniotic pregnancies. The neonatal morbidity in terms of respiratory distress syndrome (P < .001), anemia (P < .01), and intraventricular hemorrhage (P < .001) were higher in dichorionic triamniotic compared with trichorionic triamniotic triplets. The premature rupture of membrane (odds ratio, 7.5; 95% CI, 3.5-15.7) and twin-twin transfusion syndrome (odds ratio, 14.9; 95% CI, 6.6-4) were independent risk factors for perinatal death.

CONCLUSION

In spontaneously conceived triplets, the incidence of dichorionicity was 44%. The dichorionic triamniotic triplets have a 5.5-fold higher risk of adverse perinatal outcome predominantly because of twin-twin transfusion syndrome and premature rupture of membranes.

Extreme Parity and the Risk of Stillbirth

OBJECTIVE

We examined the relationship between extreme parity and risk for stillbirth in the United States.

METHODS

Singleton deliveries at 20 weeks of gestation or later in the United States from 1989 through 2000 were analyzed. Risk for stillbirth in women with 1-4 (moderate parity, category I), 5-9 (high parity, category II), 10-14 (very high parity, category III), and 15 or more (extremely high parity, category IV) prior live births were computed using logistic regression.

RESULTS

Overall, 27,069,385 births, including 1,206 to extremely high parity mothers, were analyzed. Of the 81,386 stillbirths, 71,623 (2.8/1,000), 9,206 (5.0/1,000), 531 (14.4/1,000), and 26 (21.6/1,000) cases occurred among category I, category II, category III, and category IV gravidas, respectively. With category I as referent category, the odds ratio for stillbirth increased consistently with ascending parity after adjusting for potential confounders: category II (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.02-1.07), category III (OR 1.97, 95% CI 1.81-2.15), and category IV (OR 2.31, 95% CI 1.56-3.42) (P for trend < .001). Among extremely high parity women (category IV), the odds ratio for stillbirth also increased with unit increment in the number of prior live births: 15 (OR 2.72, 95% CI 1.29-5.74), 16 (OR 3.14, 95% CI 1.17-8.41), 17 (OR 6.11, 95% CI 2.56-16.5), and 18 or more prior live births (OR 16.17, 95% CI 8.77-29.82) (P for trend < .001).

CONCLUSIONS

The risk for stillbirth is substantially elevated among very high and extremely high parity women, and care providers may consider these groups for targeted periconceptional counseling.

LEVEL OF EVIDENCE

II-2.