Abstract

A retrospective cohort study was carried out to investigate the influence of body mass index (BMI, kg/m²) on miscarriage in a population of 860 pregnant women aged 17 - 36 years, residents of a small city in the middle of Russia. BMI varied from 16 to 32, average value - 22.8 kg/m². The number of miscarriages is 49 (5.7% of all pregnancies). With the distribution of women by the BMI, the spontaneous abortions rate revealed U-shaped trajectory. The smallest proportion, 1.6%, had 189 women with 22-23.9 kg/m² - optimal interval. The highest proportion, 7.8%, had 416 women with underweight. Among 248 women with overweigh there were 5.3% miscarriages. A similar nonlinear dependence with BMI had early toxicosis, pre-labor rupture of the membranes, obstetrical bleeding, weak uterus labor, defects of placenta, cesarean section, fetal hypoxia. The sum of previous pregnancies (childbirths, artificial abortions, spontaneous miscarriages) turned out to be the smallest at a low BMI and the highest at a high BMI. The idea of underweight as a global risk factor of reproductive disturbance is being formed. The nature of this relationship remains poorly understood. The population-based character of the study allows to transfer its results to the national level. The numbers of excess miscarriages in the opposite groups were calculated. The excess losses at low BMI amounted 25.2 cases, or 51.4% of 49 miscarriages. At the high BMI, excess losses amounted 9.9 cases, or 20.2% of all miscarriages. The total excess loss amounted 35.1 cases or 76.6%. This means, that three quarters of spontaneous abortions were caused by inadequate BMI for pregnant women. It is logical to assume, if all pregnant women will have BMI in the range of 22-23.9 kg/m², the number of spontaneous abortions will reduce approximately by three quarters of the existing level. Plus, stimulation of fertility will provide the fetus conceptions growth, resulting in the birth rate elevation.

Keywords: Body Mass Index; Miscarriage; Population; Pregnancy; Spontaneous Abortions; Underweight; Overweigh; Nonlinear Dependence; Early Toxicosis; Pre-Labor Rupture of the Membranes; Obstetrical Bleeding; Weak Uterus Labor; Defects of Placenta; Cesarean Section; Fetal Hypoxia; Childbirths

References

1. https://data.woridbank.org/indicator/SP.DYN.TFRT.IN
2. Oliver A and Overton C. “Diagnosis and management of miscarriages”. Practitioner1771 (2014): 25-28.
3. Bruckner TA., et al. “Spontaneous pregnancy loss in Denmark following economic downturns”. American Journal of Epidemiology 8 (2016): 701-708.
4. Wall KM., et al. “Miscarriage among women in the United States Women’s Interagency HIV Study, 1994-2017”. American Journal of Obstetrics and Gynecology 4 (2019): 347.e1-347.e13.
5. Walter MI and Alvarado MS. “Clinical aspects of miscarriage”. American Journal of Maternal Child Nursing 1 (2018): 6-12.
6. Hogue CJ. “Invited commentary: preventable loss is a public health problem”. American Journal of Epidemiology 8 (2016): 709-712.
7. Larsen EC., et al. “New insights into mechanisms behind miscarriage”. BMC Medicine 11 (2013): 154.
8. Valeva Z., et al. “High and low BMI increase the risk of miscarriage after IVF/ICSI and FET”. Human Reproduction 4 (2008): 878-884.
9. Helgstrand S and Andersen A-M N. “Maternal underweight and the risk of spontaneous abortion”. Acta Obstetricia et Gynecologica Scandinavica 12 (2005): 1197-1201.
10. Blsells M., et al. “Systematic review and meta-analysis on the association of prepregnancy underweight and miscarriage”. European Journal of Obstetrics and Gynecology and Reproductive Biology 207 (2016): 73-79.
11. Waaler H Th. “Height, Weight and Mortality. The Norwegian Experience”. Acta Medica Scandinavica, Supplementum 679 (1984): 1-56.
12. Gundarov IA and Polessky VA. “Preventive medicine at the turn of the century. From risk factors to health reserves and social prevention”. GEOTAR-Media. M (2016).
13. Sandahl B. “Smoking habits and spontaneous abortion”. European Journal of Obstetrics and Gynecology and Reproductive Biology 1 (1989): 23-31.