Multifetal gestations after traumatic brain injury: a nationwide register-based cohort study in Finland

BACKGROUND: There is a paucity of information regarding the association between traumatic brain injuries (TBIs) and subsequent multifetal gestations. Since TBIs are known to negatively affect the neuroendocrine system, we hypothesized that the functions of the whole reproductive system might be disturbed as a result. The aim of this study is to determine the association between previous TBIs and the risk of multifetal gestations using nationwide registers. METHODS: In this retrospective register-based cohort study, data from the National Medical Birth Register (MBR) were combined with data from the Care Register for Health Care. All fertile-aged women (15–49 years) who had sustained a TBI before pregnancy were included in the patient group. Women with prior fractures of the upper extremity, pelvis, and lower extremity were included in the control group. A logistic regression model was used to assess the risk for multifetal gestation after TBI. Odds ratios (ORs) and adjusted odds ratios (aOR) with 95% confidence intervals (CIs) between the groups were compared. The model was adjusted by maternal age and maternal BMI during pregnancy and previous births. The risk for multifetal gestations were evaluated during different periods following the injury (0–3 years, 3–6 years, 6–9 years, and 9 + years). RESULTS: A total of 14 153 pregnancies occurred after the mother had sustained a TBI, and 23 216 pregnancies occurred after the mother had sustained fractures of the upper extremity, pelvis, or lower extremity. Of these, 201 (1.4%) women had multifetal gestations after TBI and 331 (1.4%) women had multifetal gestations after fractures of the upper extremity, pelvis, or lower extremity. Interestingly, the total odds of multifetal gestations were not higher after TBI when compared to fractures of the upper extremity, pelvis, and lower extremity (aOR 1.04, CI 0.86–1.24). The odds were highest at 6–9 years (aOR 1.54, 1.03–2.29) and lowest at 0–3 years (aOR 0.84, CI 0.59–1.18). CONCLUSION: The risk for multifetal gestations after TBIs was not higher than after the other traumas included in this study. Our results provide good baseline information on the effects of TBIs on the risk for multifetal gestations, but further research is required on this topic.