Assessing social status effects on age of primiparity in Polish women
Authors: Kaczmarek Maria 
Published: January 2014

The maternal first birth age is an important predictor of the size, composition and future growth of population and a wide range of birth outcomes such as birth weight, multiple births, and birth defects.
This paper aims to test the hypothesis that age of mothers at first childbirth depends on their socio-economic status and lifestyle behaviour. The examined sample emanated from the WOMID national cross-sectional survey on middle-aged women’s health and life quality in 2000–2004, and it consisted of 1,924 parous women born between 1953 and 1969 and aged 35–45 years at the time of examination. Social status was defined by place of residence, educational attainment, employment status, financial strain, and lifestyle behaviour by physical activity, cigarette smoking, alcohol use, weight status and self-reported health status.
The association of age at first childbirth with social status characteristics was adjusted to marital status and use of oral contraceptives (OCU). Multiple correspondence analysis (MCA) was used to cluster studied variables. Predictive factors for first childbirth timing were determined by a factorial design with the multi- way ANOVA and their interactions. The odds ratios of the factors associated with later maternal age at first childbirth were evaluated through multiple logistic regressions with backward elimination. Statistics for this analysis were performed using STATISTICA software, Version 10.0 (StatSoft Polska). It was found that large city residents with higher educational levels, currently employed and without financial strain, non-smoking cigarettes and drinking alcohol, participating in physical exercises and maintaining proper weight and oral contraceptive users were more likely to delay their first childbirth over the median age of 23 years, than their counterparts. The most important predictors of the maternal first birth age were: educational attainment (F=19.8; p<0.001), place of residence (F=4.2 p<0.021), employment status (F=3.7; p=0.026), tobacco use (F=5.0; p=0.007), and use of oral contraceptives (F=3.6; p=0.033),. They explained 15% of the total variance in the maternal first birth age. The probability of delivering first child at more advanced age was almost two times higher for large-city residents than for rural counterparts (OR=1.58); five times higher for women with better educational qualifications as compared to primarily educated peers (OR=5.24). Currently employed women were 1.5 times more likely to be primiparous at more advanced age than the unemployed counterparts (OR=1.5). Current smokers were 1.3 times less likely than their never smoked peers to deliver a child at older age (OR=0.75). The OC users were 1.5 times more likely for delaying childbirth than never OCU counterparts. The study have revealed key sets of social predictor variables for maternal first birth age. They include: place of residence, educational attainment and employment status, use of oral contraceptives and smoking habit. Women’s education appears to be the most predictive factor for entering the motherhood.