Gestational age within normal range and infants’ health and temperament at 3-months of age

Abstract

Objective: To examine the association between gestational age (GA) at birth across the normal GA spectrum (37–41 weeks) and the temperament and health of 3-month old infants.

Methods: The sample comprised 242 “low-risk” mothers and infants without chronic illnesses or severe pregnancy complications. Infant temperament was defined by three constructs: Negative Affectivity (NA), Extraversion, and Regulation, assessed by parents’ reports on the Infant Behavior Questionnaire. Infants’ health was defined as the number of nonroutine doctors’ visits attended by the infants since their release from the hospital after birth. Analyses employed a continuous measure of GA to assess outcomes across GAs and a categorical measure (37, 38, 39–41 weeks GA) to examine contrasts.

Results: Extraversion was positively related to GA primarily due to the lower scores of infants born at 37 weeks compared to infants born at 39–41 weeks GA. NA showed a similar effect. The odds of infants born at 37 weeks attending a nonroutine medical visit were 2.8 times that of infants born full-term.

Discussion: Infants born at 37 weeks GA express less affect and use more nonroutine medical services than do infants born at 39–41 weeks GA. The findings underscore the importance of considering the risks of pregnancy prolongation with the developmental risk associated with early-term delivery.

Keywords:

• Affect research
• childbirth
• obstetrics
• pregnancy
• child adjustment

Acknowledgements

The authors thank research assistants Nomi Ban, Sara Burstin, Polly Hyams Sherman, Mika Inbar, Linor Tzumer, Nurit Almagor, Noa Bar Ziv, Ortal Bhoknik, Noa Gohar, Irit Goldner, Yael Hassid, Yael Millgram and Dana Nozik. We are indebted to the families that participated in the study.

Disclosure statement

All authors contributed equally to the study.

In the past year, SVF received income, travel expenses and/or research support from and/or has been on an advisory board for Pfizer, Ironshore, Shire, Akili Interactive Labs, CogCubed, Alcobra, VAYA Pharma, Neurovance, Impax and NeuroLifeSciences and has received research support from the National Institutes of Health (NIH); his institution is seeking a patent for the use of sodium-hydrogen exchange inhibitors in the treatment of ADHD; in previous years, he received consulting fees or was on advisory boards or participated in continuing medical education programs sponsored by Shire, Alcobra, Otsuka, McNeil, Janssen, Novartis, Pfizer and Eli Lilly; and he receives royalties from books published by Guilford Press and Oxford University Press.

Current Knowledge

• Many pregnancies are foreshortened without a solid medical rationale.

• Early terms births are associated with an increased risk for postnatal morbidity and for developmental problems during childhood and adolescence.

• Early perturbations of health and temperament may preempt or mediate long term developmental issues associated with early term deliveries.

What this study adds

• Three-month old Infants born at 37 weeks gestational age are less expressive than infants born full-term.

• The odds of infants born at 37 weeks attending a non-routine medical visit were 2.80 times that of infants born full-term.

• The results suggest that foreshortened gestation within normal range is associated with infants’ temperament and health.

Additional information

Funding

This study was supported by a grant from the National Institute of Child Health and Human Development (NICHD) [R01HD053586].