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Abstract
Objective
We examined whether the chest-to-head circumference ratio at birth was associated with breech presentation and transverse lie. We also described the obstetric management of such pregnancies in the Japan Environment and Children’s Study (JECS).
Methods
We performed a cross-sectional evaluation of data collected between January 2011 and March 2014 in a nationwide prospective birth cohort study, the JECS. We analyzed 83,822 non-anomalous singletons born at 34–41 weeks’ gestation to mothers with no history of previous cesareans or uterine surgery. We defined low, normal (reference group), and high chest-to-head circumference ratios as <10th percentile, 10th to 90th percentiles, and >90th percentile, respectively. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for breech presentation and transverse lie. The timing and mode of delivery of such pregnancies were examined.
Results
Breech presentation was recorded in 2.6% and transverse lie in 0.2%. A low chest-to-head circumference ratio was associated with increased rate of breech presentation (5.2%; adjusted OR 2.36, 95% CI: 2.10–2.65) and transverse lie (0.3%; adjusted OR 2.33, 95% CI: 1.50–3.60), whereas a high ratio was linked to reduced breech presentation (1.1%; adjusted OR 0.51, 95% CI: 0.39–0.66). Subgroup analysis of children delivered by cesarean (n = 7971) showed a similar association, albeit with slightly reduced strength for breech presentation. Eighty-three percent of breech births and 46.3% of transverse lie births occurred at 37–38 weeks’ gestation. Cesarean section was performed in 96.8% of breech presentations and 63.4% of transverse-lie ones.
Conclusions
These findings imply that the fetal chest-to-head circumference ratio may influence presentation at birth.
Author contributions
Naw Awn J-P: conceptualization and design, data curation, analysis and interpretation of data, drafting and revising the manuscript. Takafumi Watanabe: analysis and interpretation of data, critical revision of the manuscript. Masamitsu Eitoku: data curation, analysis and interpretation of data, critical revision of the manuscript. Keiko Yamasaki: data curation, analysis and interpretation of data, critical revision of the manuscript. Naomi Mitsuda: data curation, analysis and interpretation of data, critical revision of the manuscript. Nagamasa Maeda: analysis and interpretation of data, critical revision of the manuscript. Mikiya Fujieda: analysis and interpretation of data, critical revision of the manuscript. Narufumi Suganuma: funding acquisition, data curation, analysis and interpretation of data, critical revision of the manuscript. JECS Group members: data curation, critical revision of the manuscript. All authors have read and approved the final version.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Data availability statement
Data are unsuitable for public deposition due to ethical restrictions and legal framework of Japan. It is prohibited by the Act on the Protection of Personal Information (Act No. 57 of 30 May 2003, amended on 9 September 2015) to publicly deposit the data containing personal information. Ethical Guidelines for Medical and Health Research Involving Human Subjects enforced by the Japan Ministry of Education, Culture, Sports, Science and Technology and the Ministry of Health, Labor and Welfare, also restricts the open sharing of the epidemiologic data. All inquiries about access to data should be sent to: [email protected]. The person responsible for handling enquires sent to this e-mail address is Dr. Shoji F. Nakayama, JECS Programme Office, National Institute for Environmental Studies.