A study published in the journal Sleep and Breathing found sleep quality influenced newborn weight in a gender-specific and trimester-specific way.
Li Hong, MD, of the reproductive genetic center at the Suzhou Affiliated Hospital of Nanjing Medical University in the Suzhou Municipal Hospital in China and colleagues performed the study. Researchers recruited 1344 women from 2 hospitals in Suzhou and Nanjing who were planning to use in-vitro fertilization (IVF). The average age of study participants was 31.3 years. Participants in the study were selected if they had not yet IVF at the time of enrollment, subsequently became pregnant with only 1 child, received prenatal and birth care from the study hospital, and provided written informed consent.1 Women who miscarried or experienced stillbirth were excluded from the study.
Researchers conducted a prospective cohort study and used the Pittsburgh Sleep Quality Index (PSQI) to assess sleep before oocytes were obtained, and then during each pregnancy trimester. According to the authors, the PSQI includes 18 questions about subjective sleep quality, the time it takes to fall asleep, sleep duration, length of actual sleep, sleep disturbances, use of sleep medication, and daytime dysfunction.1 Participants self-report questions from a scale of 0 (no difficulty) to 3 (severe). PSQI is scored between 0-21, and the authors said scores of 5 and above showed poor sleep.
Hong and colleagues obtained information on premature birth, normal birth, and birth weight from electronic medical records. Researchers then used a generalized estimating equation model to measure the associations between newborn weight and sleep quality.1 They used a general linear model to find which sleep issues most affected birth weight.
Researchers reported that women reported poor sleep quality before oocytes were obtained and through all 3 trimesters. Hong and colleagues said that “19.3%, 29.9%, 16.2%, and 14.4% reported poor sleep quality before oocyte retrieval, in the first trimester, in the second trimester, and in the third trimester, respectively, and the mean PSQI score in the first trimester was the highest (4.6±2.5).”
Hong and colleagues reported that while two studies found mothers of naturally conceived pregnancies have the worst sleep quality during the third trimester, mothers using IVF conception had the worst sleep quality in the first trimester.2,3 “This difference is not surprising given that a previous study showed a relationship between socio-psychological pressure and poor sleep, and women with IVF conception showed more anxiety than women with natural conception in the first trimester,” the authors wrote.1,4
Researchers said many studies have previously shown that poor sleep quality can impact both the mother’s health and fetal growth, and that birth weight is a strong predictor of newborn health. “Birth weight can reflect growth and development in the uterus; it has been widely reported that low birth weight may lead to complications such as infection and necrotizing enterocolitis,” Hong and colleagues said.1
The study results found poor sleep quality during the first and second trimesters for IVF pregnancies had the most impact on reducing birth weight, but only in female infants (OR=3.03, 95% CI=1.04to 9.71, P=0.044).1 Researchers did not find a correlation in male infants (OR=1.64, 95% CI=0.68 to 3.99, P=0.271).1 Hong and colleagues noted that sex preferences for male babies in China may have influenced the anxiety of mothers pregnant with girls, and thus had a negative effect on their sleep quality.
“The results of the study suggest that early screening and interventions focused on improving sleep quality may be useful to reduce adverse outcomes related to poor sleep. Sleep intervention or psychological counseling during pregnancy may be of benefit to fetal well-being,” Hong and colleagues concluded.1