We hypothesize that a decline in GFR would increase the probability of having a CDMR, ceteris paribus, because low GFR increases the social value of newborns and increases women's preference for c-sections over vaginal deliveries.
In the model, the dependent variable was a mutually exclusive discrete choice of the delivery mode: vaginal delivery, c-section, or CDMR.
Delivery modes were determined based on the NHI diagnosis-related groups (DRG) code in the NHIRD (Lin and Xirasagar 2004; Xirasagar and Lin 2004): vaginal delivery (DRG = 0373A), medically indicated c-section (DRG = 0371A), and CDMR (DRG = 0373B, maternal request c-section and no conditions in the International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) required).
During our study period, the NHI reimbursement rate for medically indicated c-sections is twice that of a CDMR or a vaginal delivery.
Women who had medically indicated c-sections and CDMR were generally older (29.
We estimated the effect of declining fertility on the use of medically indicated c-sections and CDMR by calculating the marginal effects of the logarithm of GFR and the logarithm of the lagged number of ob/gyns per 100 births in the multinomial probit model (Table 2).
In test 4, we limited our sample to women aged [greater than or equal to] 34 because prior studies indicated that women aged 34 and older were more likely to have CDMR (Lin and Xirasagar 2005).
In robustness test 3 that included only women with primary c-sections and vaginal delivery, the effect of the logarithm of GFR on the probability of having CDMR was greater, corroborating the finding that women preference for c-section increased as a result of the fertility decline.
2005), our study further suggests that a significant share of CDMR can be explained by declining fertility.