according to authors of a large, international observational study.
Dr. Judette Marie Louis
There was no significantly increased risk of stillbirth, preterm birth, or small-for-gestational-age birth in the next pregnancy for women who conceived in that 12-month time period, according to results of the study, which was based on birth records for nearly 14,500 women in Finland, Norway, and Australia.
“We hope that our findings can provide reassurance to women who wish to become pregnant or unexpectedly become pregnant shortly after a stillbirth,” study author Annette K. Regan, PhD, of Curtin University, Perth, Australia, said in a statement on the study, which appears in The Lancet.
Judette Marie Louis, MD, MPH, said that while data are conflicting on optimal interpregnancy interval following stillbirth, large population-based studies such as this one may provide an indication of the relative safety of an interval of 12 months or less. (She was not involved in this study.)
“This paper is good news for a lot of women,” Dr. Louis, associate professor of obstetrics and gynecology at the University of South Florida, Tampa, said in an interview. “After a stillbirth, it’s such a traumatic experience that some do want to move on, and these findings suggest that, yes, you don’t have to wait that long to have a successful pregnancy.”
These results are for women living in relatively high-income countries, so the findings might not apply to every population, she added. Dr. Louis was the first author of a recent interpregnancy care consensus statement by the American College of Obstetricians and Gynecologists and the Society of Maternal-Fetal Medicine, and was asked to comment on this study.
The World Health Organization recommends interpregnancy intervals of 2 years or more after live births and 6 months or more after miscarriage, but currently has no specific recommendations on the optimal interpregnancy interval after a stillbirth, according to Dr. Regan and her colleagues.
“Because length of gestation might affect nutrient concentrations and health status in women, it is plausible that the optimal interval after stillbirth is somewhere between the optimal interval after miscarriage and live birth,” they said in their report.
Researchers for two previous studies also have reported on the link between the interpregnancy interval after stillbirth and birth outcomes in the next pregnancy, but neither was specifically designed to evaluate that outcome, they added.
Dr. Regan and her coauthors used birth record data spanning several decades from three high-income countries to identify 14,452 women who had stillbirths. Of those, 63% conceived within the next 12 months, and for 37%, it was as early as 6 months.
Overall, 2% of the subsequent pregnancies ended in stillbirth, while 9% were small-for-gestational-age and 18% were preterm, according to the report.
In analyses adjusted for variables such as age, smoking, and education level, there was no association between short interpregnancy intervals and subsequent stillbirths, compared with longer intervals (24-59 months), with odds ratios of 1.09 for an interval shorter than 6 months and 0.90 for 6-11 months.
Likewise, there was no link between shorter intervals and subsequent small-for-gestational-age birth, with odds ratios of 0.66 for less than 6 months and 0.64 for 6-11 months, and no link between interval and subsequent preterm births, with odds ratios of 0.91 for both short-interval groups.
That data could be useful to health care providers who do postpartum counseling after stillbirths, and could potentially inform future recommendations on pregnancy spacing, Dr. Regan and her coauthors said.
“These results apply to a large proportion of women conceiving after a stillbirth,” they noted.
This study included countries with access to universal health care, with populations that are mostly white, so the results may not apply to low- or middle-income countries without universal health care or with significant ethnic minority populations, they added.
Dr. Regan and her colleagues declared no competing interests related to the study, which was funded the National Health and Medical Research Council of Australia, among other sources.
SOURCE: Regan AK et al. Lancet. 2019 Feb 28. doi: 10.1016/S0140-6736(18)32266-9.