Assisted reproductive interventions and multiple birth

Deformational plagiocephaly at birth: an observational study on the role of assisted reproductive technologies

BACKGROUND

Following the "back to sleep" recommendations, a striking rise in deformational plagiocephaly (DP) occurred. However, additional maternal, pregnancy and infant conditions may play a role.

OBJECTIVES

We aimed to evaluate the prevalence of and risk factors for DP at birth. Additionally, given the association between assisted reproductive technologies (ART) use and unfavorable pregnancy events, we explored the association between ART and DP.

PATIENTS AND METHODS

A total of 413 neonates >33 weeks born at L. Sacco Hospital (Milan, Italy) from May 2011 through to January 2012 were enrolled. Data regarding parental, conceivement, pregnancy and delivery characteristics were recorded. Infants' skull measurements, including the oblique cranial length ratio (OCLR) were taken within 72 h after birth. Plagiocephaly was defined for OCLR > 105.9.

RESULTS

The prevalence of DP was 20.3%. It was associated with twinning (OR 5.0; 95%CI 2.22-11.1), pregnancy complications (OR 2.86; 95%CI 1.49-5.26), prematurity (OR 2.13; 95%CI 0.98-4.54), ART use (OR 2.00; 95%CI 0.90-4.35) and male gender (OR 1.79; 95%CI 0.94-2.50). Adjusting for multiple pregnancies however, the association between ART and DP disappeared.

CONCLUSION

Results show that offspring of pregnancies conceived through ART do not have increased risk of DP. However, our numbers are small thus larger studies are needed for definitive conclusions.

Risk of birth defects increased in multiple births

BACKGROUND

Previous studies inconsistently suggest that there may be an association between birth defects and multiple births.

METHODS

Data were obtained from Zhejiang Hospital-Based Birth Defects Surveillance System during 2007 to 2009. There was a total of 545,018 pregnancies, including 537,593 singleton pregnancies, and 7425 multiple pregnancies (14,606 twins and 366 triplets). Odds ratio (OR)and confidence interval (CI) for birth defects were calculated for the singletons and multiple births.

RESULTS

The rate of birth defects in multiple births was 444.16 per 10,000 births versus 266.97 per 10,000 births in singletons (OR, 1.69; 95% CI, 1.57-1.84). A significant risk of birth defects was observed in 9 of 23 categories in multiple births. Both the multiple births and singletons with birth defects exhibited a similar proportion of single malformation, male children, and the mother living in a city. The multiple births with birth defects were delivered earlier (t = 7.90, p < 0.001) at a lower birth weight (t = 17.53, p < 0.001) compared to singletons with birth defects. The proportion of an antenatal diagnosis was higher in singletons compared with multiple births (p < 0.001). The multiple births with birth defects had a higher proportion of live birth and early neonatal death (p < 0.001).

CONCLUSIONS

An increased risk of birth defects in multiple births compared with singletons was confirmed.

Trends in the probability of twins and males in California, 1983-2003

This study examines the probability of twins by birth year, maternal race-ethnicity, age, and parity and the influences of these demographic factors on the probability of male in twins and singletons in a large, racially diverse population. Recent publications note steep increases in twin births while the probability of male births has been reported to vary by parental race-ethnicity and age and birth order. Probability of male stratified by plurality has not been investigated in California prior to this study. Cubic spline estimates and Poisson regression techniques were employed to describe trends in twins and males using California vital statistics birth and fetal death records over the period from 1983-2003. This study includes 127,787 twin pair and 11,025,106 singleton births. The probability of twins varied by birth year, maternal race-ethnicity, age, and parity. The probability of twins increased by 10.1% from 1983-1992 and increased by 20.1% from 1993-2003, nearly doubling the previous increase. All maternal race-ethnicity groups showed increases in probability of twins with increasing maternal age. Parous women compared to nulliparous women had larger increases in the probability of twins. The probability of males in twins decreased from 1983-1992 and increased from 1993-2003; while in singletons the probability appeared unchanged. These findings show increases in the probability of twins in California from 1983-2003 and identify maternal age, race-ethnicity, and parity groups most likely to conceive twins. The cause of the increase in twins is unknown but coincides with trends towards delayed childbearing and increased use of subfertility treatments.

Global epidemiology of multiple birth

Multiple births, which account for approximately 3% of births and 14% of infant deaths, are increasing in frequency. Multiple birth rates began to decline in the 1950s, reaching a minimum in the 1970s and rising since then. Both twin and triplet rates followed the same rising trend until 1998, after which triplet birth rates began to decline while twin birth rates continued to rise. Rising maternal age is associated with rising frequency of dizygotic twinning up to 37 years of age. Older maternal age, associated with the social trend to delayed child bearing, accounts for 25- 30% of the rise in multiple birth rates since 1970. The resulting rise in the prevalence of infertility has given rise to unprecedented use of ovarian stimulation treatments that stimulate the development of multiple oocytes. Assisted reproduction technology and ovulation stimulation with clomiphene citrate or gonadotrophins without assisted reproduction account for similar proportions of both twin births (20- 30%) and triplet births (30- 40%). The fall in triplet rates since 2000 is reassuring, but fetal reduction of high order pregnancies may be a factor in rising twin rates. Continuing attention is needed to all possible means of minimizing triplet pregnancies.

Perinatal loss among twins

OBJECTIVE

We evaluated prenatal factors related to perinatal loss in twins, using medical records and death certificates, to determine the main perinatal event that contributed to babies' deaths.

DESIGN

This was a retrospective cohort study of 550 monochorionic diamniotic or diamniotic dichorionic twins who were delivered at Kaiser Permanente Colorado between 1994 and 2001.

MAIN OUTCOME

The main outcome of the study was perinatal loss (stillbirth or neonatal death).

OUTCOMES MEASURES

Select maternal risk factors (maternal age, race, marital status, assisted conception, past history of preterm birth, cigarette smoking, and placentation) were included in the univariable and multivariable logistic regression analysis. Data on these risk factors came from review of records from our multiple-birth perinatal database. A comprehensive review of clinical events recorded in the medical records and on the death certificate was conducted to assess the main event that contributed to the loss.

RESULTS

In the cohort of 1100 babies, there were 12 stillbirths and 34 neonatal deaths, with an overall frequency of perinatal loss of 4.2%. We found a strong association between a monochorionic diamniotic placentation and perinatal loss (adjusted odds ratio, 3.9; 95% confidence interval, 2, 7.7). At delivery, placental pathology and spontaneous preterm birth accounted for 36% and 41%, respectively, of the clinical events contributing to the demises. Compared with the medical record, review of death certificate information did not contribute significantly to the understanding of the sequence of perinatal events leading to the demise.

CONCLUSIONS

We conclude that loss in twins is most strongly associated with monochorionic diamniotic placentation. Although this condition is not preventable, early identification (by ultrasound) and referral to subspecialists may decrease the chances of perinatal loss. Prevention of spontaneous preterm birth in all women remains an important initiative in obstetric care to reduce perinatal mortality and neonatal morbidity. We believe that improvements in the reporting on death certificates will allow future research on large data sets and may provide further insight into perinatal loss in twins. We emphasize the importance of a comprehensive clinical review of each case of perinatal loss to fully understand the sequence of clinical events leading to this adverse pregnancy outcome.

Pregnancy rate, multiple pregnancy rate, and embryo quality: Clues for single blastocyst transfer from double blastocyst transfer in an unselected population

Objective:  Minimizing multiple pregnancy is a priority in assisted reproduction. As implantation rates are critical to success and reduce multiple pregnancy, we investigated whether blastocyst grade determined implantation rate following double blastocyst transfer in unselected cases. Materials and Methods:  We studied 69 three-cleavage stage embryo transfers and 64 two-blastocyst transfers. Two blastocysts, or one when two blastocysts were not available, were transfered after evaluating the grade of blastocysts. The difference in pregnancy and implantation rates to patient age, the number of retrieved oocytes and grade of blastocysts were analyzed. Results:  Blastocyst and grade 3AA rates per fertilized egg were 50.3% and 26.0%, respectively. Following two-blastocyst transfer, pregnancy rate per transfer, implantation rate per embryo, and multiple pregnancy rate per pregnancy were 39.1%, 26.5%, and 24.0%, respectively. Two-blastocyst transfer achieved implantation more often than three-cleavage-stage embryo transfer, but did not reduce multiple pregnancy. Pregnancy, implantation, and multiple pregnancy rates did not reflect maternal age. Higher pregnancy and implantation rates per transfer were attained for with six or more oocytes retrieved or transfer of two-blastocyst graded 3AA or higher especially when two or more blastocysts graded 3AA or higher are available, but the latter showed a high multiple pregnancy rate (38.5%). Conclusions:  Single embryo transfer could be carried out when two or more blastocysts of grade 3AA or higher have been developed. (Reprod Med Biol 2005; 4: 153-160).

Why and how should multiple pregnancies be prevented in assisted reproduction treatment programmes?

Although most professional societies have issued guidelines to diminish the number of embryos to be transferred during assisted reproductive techniques, the incidence of multiple pregnancies remains unacceptably high. The burden of morbidity and mortality seems to increase substantially with each fetus in a multiple gestation. As a result, there has been growing debate on the need to prevent multiple pregnancies. The infertility specialists who can solve the infertility problem are usually shielded from the complications of multiple pregnancies. If they were involved in the delivery and, more particularly in the care of multiple pregnancies (both financially and socially), their attitude would probably change. IVF centres should gradually reduce the mean number of embryos per transfer in terms of the cost:benefit ratio. A further reduction to one single embryo per transfer in good cases would be similarly acceptable. Laboratory expertise is of vital importance, especially in terms of embryo culture, embryo selection, and freezing and thawing techniques in embryo transfer programmes for reducing the number of transferred embryos.

Reducing the incidence of twins and triplets

Multiple pregnancy rates remain high after assisted conception because of a misconceived assumption that transferring three or more embryos will maximize pregnancy rates. Maternal morbidity is sevenfold greater in multiple pregnancies than in singletons, perinatal mortality rates are fourfold higher for twins and sixfold higher for triplets, while cerebral palsy rates are 1-1.5% in twin and 7-8% in triplet pregnancies. Therefore, multiple pregnancies must be considered a serious adverse outcome of assisted reproductive techniques. Primary prevention of multiple pregnancies is the solution. The overwhelming evidence presented in this chapter demonstrates that limiting the embryo transfer in in vitro fertilization to two embryos would significantly reduce adverse maternal and perinatal outcomes by reducing the incidence of high order multiple pregnancies without reducing take-home-baby rates. Secondary prevention by multifetal pregnancy reduction is effective, but not acceptable to all patients. New developments in blastocyst culture, single embryo transfer, embryo cryopreservation and pre-implantation aneuploidy exclusion, should allow improvements in pregnancy rates without increasing multiple pregnancies.

Assessing the risk of multiple gestation in gonadotropin intrauterine insemination cycles

OBJECTIVE

The purpose of this study was to analyze factors for their ability to predict multiple gestation in women who undergo controlled ovarian hyperstimulation with gonadotropins (follicle-stimulating hormone/human menopausal gonadotropin) and intrauterine insemination.

STUDY DESIGN

This was a retrospective analysis of the clinical and laboratory variables that are associated with multiple gestation. Data for 6 variables in 678 cycles of gonadotropin/intrauterine insemination between 1990 and 1999 were analyzed with survival analysis, Cox regression analysis, and multiple logistic regression.

RESULTS

There were 99 clinical pregnancies among 678 cycles (14.6% per cycle) in 306 women. Of the 14 women with multiple gestations (14.1% of pregnancies), 11 women had twins, 2 women had triplets, and 1 woman had quadruplets. Age, days of gonadotropin treatment, total dose of gonadotropin, and number of follicles that were >or=15 mm at the time of human chorionic gonadotropin administration were statistically significant predictors of multiple gestation in >or=1 of the statistical models.

CONCLUSION

The risk of multiple gestation with controlled ovarian hyperstimulation/intrauterine insemination in this study was relatively low. In addition to age, several controllable variables that are associated with multiple gestation were identified.