Couples who attempt to conceive within three months after losing an early pregnancy, defined as less than 20 weeks gestation, have the same chances, if not greater, of achieving a live birth than those who wait for three months or more, according to a National Institutes of Health study.
This finding, published in Obstetrics & Gynecology, questions traditional advice that couples should wait at least three months after a loss before attempting a new pregnancy. The World Health Organization, for example, recommends waiting a minimum of six months between a pregnancy loss and a subsequent attempt.
"Couples often seek counseling on how long they should wait until attempting to conceive again," said Enrique Schisterman, Ph.D., chief of the Epidemiology Branch at NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and senior author of the study. "Our data suggest that women who try for a new pregnancy within three months can conceive as quickly, if not quicker, than women who wait for three months or more."
Previous studies of pregnancy spacing have focused on when women should become pregnant after experiencing a loss, but few have addressed the question of when couples should start trying to conceive.
In the current study, researchers analyzed data from the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial, a multisite block-randomized, double-blinded, placebo-controlled trial that took place from 2007 to 2011. The trial, which evaluated the effect of daily low-dose aspirin on reproductive outcomes in women with a history of pregnancy loss, enrolled 1,228 women aged 18 to 40 years.
NICHD investigators concentrated on 1,083 of these women, more than 99 percent of whom had lost a pregnancy at less than 20 weeks gestation. None of the women had either of two potential complications of pregnancy: a tubal (ectopic) pregnancy or a molar pregnancy (growth of abnormal fetal tissue in the uterus). The participants were followed for up to six menstrual cycles and, if they became pregnant, until the outcome of their pregnancy was known.
The researchers found that more than 76 percent of the women attempted to conceive within 3 months after losing a pregnancy. Compared to those who waited longer, this group was more likely to become pregnant (69 percent vs. 51 percent) and to have a pregnancy leading to a live birth (53 percent vs. 36 percent). The investigators did not observe any increase in the risk of pregnancy complications in this group.
"While we found no physiological reason for delaying attempts at conception following a pregnancy loss, couples may need time to heal emotionally before they try again," said Karen Schliep, Ph.D., a postdoctoral fellow in the NICHD Epidemiology Branch at the time of the study and primary author of the study. "For those who are ready, our findings suggest that conventional recommendations for waiting at least three months after a loss may be unwarranted."