Browsing by Subject "Fertility"

This dissertation consists of two original empirical studies on the determinants of teenage childbearing in the United States. The first study examines the impact of educational attainment on teenage childbearing, using school entry laws as an instrument for education and a highly detailed North Carolina administrative dataset that links birth certificate data to school administrative records. I show that being born after the school entry cutoff date affects educational success in offsetting ways, with a negative impact on years of education but positive impact on test scores. Using an IV regression strategy to distinguish the impacts of years of education and test scores, I show that both educational measures have negative impacts on teenage childbearing.

The second study examines potential causes of the decline in the U.S. teenage birth rate between 1991 and 2010. Using age-period-cohort models with Vital Statistics birth data and Census population counts, I show that the decline was driven by period changes in the early 1990s but by cohort changes between the mid-1990s and mid-2000s. I also use a difference-in-differences model to investigate the extent to which social policies in the 1970s-1980s can explain these cohort changes. The evidence suggests that while legalization of abortion for adult women and unilateral divorce laws had a significant impact on teenage birth rates in the 1990s-2000s, abortion legalization is unlikely to be a major explanation for the observed decline.

In this dissertation, I examine at the aggregate and individual levels, why contemporary fertility preferences diverge from actual fertility. I use three waves of cross-sectional survey data from the National Family Health Surveys from India (also known as the Indian Demographic and Health Surveys), fielded in 1992-3, 1998-9 and 2005-6 to investigate the disjuncture between preferences and behavior. The first empirical chapter outlines and operationalizes a new framework to decompose the incongruence between stated preferences and actual fertility into a set of parameters, such as unwanted births, gender preference and postponement of births to later ages, each of which varies in its level and intensity between societies and over time. By delineating the societal constraints that women do not incorporate in their childbearing intentions, this model provides a useful framework to explain variability in fertility in contemporary intermediate- and low-fertility populations. Equally important, the framework provides avenues to enquire into the fundamental structural and cultural correlates producing differences between family size preferences and actual fertility.

Subsequent empirical chapters explore various aspects of fertility preferences in detail. The second chapter probes a key socioeconomic correlate of individual-level fertility preferences, namely educational differences in preferences. In brief, I find that educational differences in family size preferences have considerably converged over time using two-way fixed effects models. However, there is still considerable heterogeneity in the implementation of preferences (as manifested by the use of contraception). Accordingly, in the third chapter, I analyze the multilevel sources of variation in the use of contraception by young women, given that they express a preference to space or stop childbearing. Using multilevel models, I find that community norms play a strong role in the use of contraception by young women to meet their fertility preferences to space or stop childbearing. I argue that community norms are an influential determinant of young women's ability to regulate their own fertility - serving to enhance or constrain their use of contraception to either space or stop childbearing.

Overall, findings from this dissertation highlight the macro-level factors that explain variation in contemporary fertility, of which fertility preferences emerge as a critical parameter. This dissertation also illuminates the growing convergence of fertility preferences across socioeconomic categories, while focusing attention on local community forces that influence fertility behavior even in the face of women's stated preferences.

This dissertation considers incentives arising from equilibrium influences that affect the sequence of decisions that lead to family formation. The first chapter examines how state regulations directly aimed at abortion providers affect the market for abortion in the United States. Estimates from a dynamic model of competition among abortion providers show that regulations' main impact is on the fixed costs of entry for providers. Simulations indicate that the removal of regulations would promote entry and competition among abortion providers, and because abortions are found to be price sensitive, this would lead to increases in the number of abortions observed. The second chapter tests if an important negative externality of abortion access exists, namely whether abortion access makes prospective fathers more likely to leave pregnant women. Designing a number of empirical tests, I confirm that in some areas where abortion is more accessible women who give birth are more likely to be single mothers, rather than sharing parental responsibility with the biological father. The final chapter, which is joint work with Peter Arcidiacono and Marjorie McElroy, examines how gender ratios influence bargaining power in romantic relationships between men and women. Gender ratios, by influencing the prospects of matching, allow us to estimate preferences for various match characteristics and activities. We find men prefer sexual relationships more than women at high school ages, and that men and women trade off their preferred partner for an increased chance of matching.

An aspect of ovary structure and function that has been given little attention is the rete ovarii (RO). Although the RO appears in drawings of the ovary in early versions of Gray’s Anatomy, it has disappeared from recent textbooks, and often is dismissed as a ‘functionless vestige’ of the adult ovary. The role, function, and development of the RO have largely evaded understanding by scientists for the past 154 years since its first description. In the process of studying ovarian morphological development, we identified a marker, PAX8, that strongly labels the RO and reveals that it is an actively developing tripartite structure consisting of the intraovarian (IOR), connecting (CR), and extraovarian rete (EOR), all three of which persist in adult life. The early RO develops within the mesonephros, alongside the Wolffian and Müllerian duct. Although both the male (Wolffian) and female (Müllerian) ductal primordia are present at the outset of gonadogenesis, only one of the two ductal systems develops. Once the male pathway is initiated, testis cells produce Anti-Mullerian hormone (AMH), leading to Müllerian ductal degeneration, and testosterone, promoting the development of the Wolffian duct and mesonephric tubules into the Rete Testis (RT), the efferent ductules, and the epididymis. In contrast, during female development, AMH is absent, and the Müllerian duct differentiates into the oviduct and uterus. These findings led to the idea that the mesonephric ducts are exclusively “male” primordia, while the Müllerian ducts are exclusively “female” primordia. This interpretation was consistent with the old idea that the RO was a degenerating structure derived from remnants of the mesonephric tubules still detectable in females. Using confocal imaging we found that the RO derives from the mesonephric tubules, but also from the first segment of the main Wolffian duct thought to only persist in XY as the Wolffian duct. We found that the Wolffian duct is severed during establishment of the RO to create the blind ended EOR, indicating the persistence of the “male” ductal system in the female reproductive tract. We also found bridges of cells from the Mullerian rudiment toward the presumptive CR (XX) and efferent ductules (XY), suggesting the intermingling of Müllerian Duct and mesonephric tubule cells in both sexes. This alters the paradigm that the mesonephric duct is exclusively a male-specific structure, while the Müllerian duct is exclusively a female-specific structure.The function and role of the RO previously heavily relied on histology and serial sections – leading to a confusion on the description and function of the RO. Some early histology of the structure, and work presented here, suggest that cells of the EOR are secretory. Using microinjections into the EOR, we found that it is fluid-filled and that luminal contents flow towards the ovary. Using proteomics and transcriptomics we found that the EOR produces proteins that are essential for ovarian function and homeostasis. These proteins, among others, are hormonally regulated. Labelling for cellular component markers revealed that a subset of the epithelial cells of the EOR are ciliated and exhibit cellular trafficking capabilities. Labelling for innervation and vasculature revealed that the cells of the EOR are closely associated with neuronal projections and vasculature. The direct proximity of the RO to the ovary suggest that it is functionally linked to the ovary and may play an important role in ovary development and homeostasis. Based on the cell biology, transcriptome and proteome of the RO,I hypothesize that the RO acts as an antennae for the ovary and plays an important role in ovary homeostasis and fertility.

After the 2012 London Summit on Family Planning, there have been major strides in advancing the family planning agenda for low and middle-income countries worldwide. Much of the existing infrastructure and funding for family planning access is in the form of supplying free contraceptives to countries. While the average yearly value of donations since 2000 was over 170 million dollars for contraceptives procured for developing countries, an ongoing debate in the empirical literature is whether increases in contraceptive access and supply drive declines in fertility (UNFPA 2014).

This dissertation explores the fertility and behavioral effects of an increase in contraceptive supply donated to Zambia. Zambia, a high-fertility developing country, receives over 80 percent of its contraceptives from multilateral donors and aid agencies. Most contraceptives are donated and provided to women for free at government clinics (DELIVER 2015). I chose Zambia as a case study to measure the relationship between contraceptive supply and fertility because of two donor-driven events that led to an increase in both the quantity and frequency of contraceptives starting in 2008 (UNFPA 2014). Donations increased because donors and the Zambian government started a systematic method of forecasting contraceptive need on December 2007, and the Mexico City Policy was lifted in January 2009.

In Chapter 1, I investigate whether a large change in quantity and frequency of donated contraceptives affected fertility, using available data on contraceptive donations to Zambia, and birth records from the 2007 and 2013 Demographic and Health Surveys. I use a difference-in-difference framework to estimate the fertility effects of a supply chain improvement program that started in 2011, and was designed to ensure more regularity of contraceptive supply. The increase in total contraceptive supply after the Mexico City Policy was rescinded is associated with a 12 percent reduction in fertility relative to the before period, after controlling for demographic characteristics and time controls. There is evidence that a supply chain improvement program led to significant fertility declines for regions that received the program after the Mexico City Policy was rescinded.

In Chapter 2, I explore the effects of the large increase in donated contraceptives on modern contraceptive uptake. According to the 2007 and 2013 Demographic and Health Surveys, there was a dramatic increase in current use of injectables, implants, and IUDs. Simultaneously, declines occurred in usage of condoms, lactational amenorrhea method (LAM), and traditional methods. In this chapter, I estimate the effect of the increase in donations on uptake, composition of contraceptive usage, and usage of methods based on distance to contraceptive access points. The results show the post-2007 period is associated with an increase in usage of injectables and the pill among women living further away from access points.

In Chapter 3, I explore attitudes towards the contraceptive supply system, and identify areas for improvement, based on qualitative interviews with 14 experts and 61 Zambian users and non-users of contraceptives. The interviews uncover systemic barriers that prevent women from consistently accessing methods, and individual barriers that exacerbate the deficiencies in supply chain procedures. I find that 39 out of 61 women interviewed, both users and non-users, had personal experiences with stock out. The qualitative results suggest that the increase in contraceptives brought to the country after 2007 may have not contributed to as large of a decline in fertility because of bottlenecks in the supply chain, and problems in maintaining stock levels at clinics. I end the chapter with a series of four recommendations for improvements in the supply chain going forward, in light of recent commitments by the Zambian government during the 2012 London Summit on Family Planning.

Current theories of marriage and family formation behavior tend to rely on the assumption that people can and do consciously plan both fertility and marriage and post-hoc intentions should align with a priori reasons for action (Fishbein & Azjen 2010). However, research shows this is not always the case and researchers have labeled inconsistencies between pre- and post- reports of intentions and behavior as retrospective bias. Researchers such as Bongaarts (1990) have tried to create models that minimize this "bias".

The Theory of Conjunctural Action is a new model that can explain, rather than explain away, this "bias" (Johnson-Hanks et al. 2011; Morgan and Bachrach 2011). This new theoretical innovation uses insights about the workings of the mind to gain a greater understanding of how individuals report family formation decisions and how and why they might change over time. In this theory, individuals experience conjunctures (or social context which exists in the material world) and use cognitive schemas (or frames within the mind through which individuals use to interpret the world around them). These schemas are multiple and the set can change over time as individuals incorporate new experiences into them.

In this dissertation, I explore how and why pre- and post- reports of intentions may be different using insights from the Theory of Conjunctural Action. In the second chapter, using data from the NLSY79 and log-linear models, I show that there are considerable inconsistencies between prospective and retrospective reports of fertility intentions. Specifically, nearly 6% of births (346 out of 6022) are retrospectively reported as unwanted at the time of conception by women who prospectively reported they wanted more children one or two years prior to the birth. Similarly, over 400 births are retrospectively reported as wanted by women who intended to have no more births one or two years prior (i.e., in the prior survey wave). The innovation here is to see this inconsistency, not as an error in reporting, but as different construals of a seemingly similar question. In other words, women may not be consciously intending births and then enacting these intentions; rather women may have different schemas (or meanings) of prospective and retrospective measures of fertility intentions.

The next chapter uses this same data to test if women use different schemas to guide their reporting of prospective and retrospective fertility intentions. Again, using insights from the Theory of Conjunctural Action, I expect that different schemas (represented by different sets of variables) predict prospective and retrospective wantedness differentially. I show that retrospective reports of wantedness are guided more by age, marital status, education, job satisfaction, and educational enrollment at birth, while prospective wantedness was guided more by number of children desired and how many children they currently have. I show four logistic models predicting wanted verses unwanted births. I then compared the model fit of logistic models predicting prospective wanted verses unwanted births using the hypothesized prospective and retrospective schema variables and I did the same for the models of retrospective wantedness. I find that when women report retrospective wantedness, they are guided more by the hypothesized variables.

Finally, in the last empirical paper, because schemas are difficult to measure, I build a methodology, Network Text Analysis, to measure schemas and to understand the schemas surrounding marriage and fertility for low-income Blacks who have not yet had children. I use interview data from the Becoming Parents and Partners Study (BPP), a sample of young, unmarried, childless adults with low incomes. I use these data to explore schemas of childbearing and marriage. Contrary to previous findings that low-income parents do not link marriage and fertility and have different requirements for marriage and fertility, I find that marriage and childbearing are indeed linked and have similar requirements for low-income Blacks prior to childbearing. Low income Blacks hold quite traditional views about the role of marriage and its sequencing vis-à-vis fertility. I argue that the material constraints to marital childbearing may lead to non-marital births and thus respondents sever schemas connecting marriage and childbearing and adopt other schemas of childbearing to provide ad hoc justifications for their behavior.