Prenatal Conditions and the Timing of Pregnancies

Conditions experienced in utero have profound consequences for outcomes later in life. Much of this evidence is based on predictable variation in the prenatal environment. Such predictable variation can be avoided by mothers timing their pregnancies; however, this point has received little attention. In this dissertation, I study the timing of pregnancies to avoid foreseeable threats to fetal health, and the implications for the relationship between prenatal conditions and long-run outcomes. The first chapter contains a summary of the existing research on the timing of pregnancies and provides a framework for analyzing the evidence. In Chapter 2, I examine if women time pregnancy to avoid Ramadan, the Islamic month of fasting. Earlier research documents that pregnancies which are in utero during Ramadan lead to lower birth- weight and a greater risk of fetal death. Using survey data from Indonesia, the worldâ s largest Muslim country, I find evidence of Ramadan avoidance. The probability of using contraceptives falls by 0.8 percentage points in the first month and by 1.2 percentage points in the second month after Ramadan, allowing mothers to conceive and give birth before the next cycle of Ramadan. Mothers learn to avoid exposure to Ramadan from their prior experience of pregnancy during Ramadan. There is no evidence of avoidance before the introduction of a program that distributed contraceptives, indicating that family planning programs may improve child health by allowing mothers to plan pregnancy to avoid predictable threats to prenatal health. In the final chapter, I study the consequences of prenatal exposure to dengue for infant health. Dengue is one of the most important mosquito-borne viral diseases in the world, yet evidence on its effects during pregnancy is inconclusive. Combining birth records data with data on dengue incidence in Puerto Rico, I find that one confirmed case of dengue per 1â 000 during pregnancy leads to 0.53-0.76 percent fewer live births. Mothers are more likely to avoid dengue exposure in a given pregnancy if they have experienced dengue during a previous pregnancy. My research suggests that predictable variation in prenatal conditions often used in the fetal origins literature may not necessarily be treated as a natural experiment.

Department dc:contributor.department

Economics

Year dc:date.issued

2016

Author dc:creator

• Karimova, Alfia

Advisor dc:contributor.advisor

• Baker, Michael

• economics
• fertility
• health
• prenatal
• timing

Handle dc:identifier.uri

http://hdl.handle.net/1807/76504

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/76504