Pregnancy intention is usually measured retrospectively, by asking mothers after a birth whether they wanted the pregnancy at that time, wanted it later or did not want it at all. That measure is valuable but scientifically complicated. A mother’s answer may be shaped by the outcome of the pregnancy, her current relationship with the child, the family’s economic conditions or the quality of healthcare she was able to obtain. These factors create what epidemiologists call endogeneity: the reported exposure—in this case an unwanted pregnancy—is entangled with other variables that also affect health. A simple comparison between wanted and unwanted pregnancies therefore cannot establish whether the pregnancy intention caused the difference in care or whether both were consequences of poverty, limited autonomy, family pressure or restricted access to services. To address this problem, Md Zobraj Hosen and Mohammad Hajizadeh used an instrumental-variable approach, a method designed to isolate variation in an exposure that is less directly connected to unmeasured confounding factors.

Their instrument was based on the sex composition of a mother’s previous children. For third and later births, the researchers compared mothers who already had at least one son and one daughter with mothers whose older children were all boys or all girls. In settings where families have preferences for a particular sex, a couple with children of only one sex may be more likely to continue having children, while a couple who already has both a son and a daughter may be more likely to regard another pregnancy as unwanted. The researchers used this pattern as a source of quasi-experimental variation. In technical terms, the instrument predicts reported pregnancy intention, but the method requires that it influence health outcomes primarily through that intention and not through some separate pathway. This is a demanding assumption, and the authors do not claim that it makes the study equivalent to a randomized trial. Instead, the analysis estimates a local average treatment effect—the effect among births whose reported pregnancy intention was actually shifted by the sex composition of previous siblings.

The pattern in maternal care was striking. In the instrumental-variable estimates, an unwanted pregnancy reduced the probability that a mother would receive at least four antenatal-care visits by 18.6 percentage points among third- and higher-order births. The likelihood of reaching at least eight visits fell by 24.7 percentage points. Antenatal care provides a series of opportunities to monitor blood pressure, detect anemia and infections, assess fetal growth, identify pregnancy complications and offer preventive interventions such as vaccination, nutritional advice and counseling. The number of visits is not the only measure of quality, and global recommendations have evolved over time, but repeated contact with trained health professionals generally increases the chance that problems will be detected before they become emergencies. A fall of nearly one-fifth in the share receiving four or more visits, and nearly one-quarter in the share receiving eight or more, represents a major loss of contact with the health system. The study does not establish precisely why care declined, but possible mechanisms include reduced emotional or financial support, delayed recognition of the pregnancy, lower household investment or barriers related to stigma and reproductive decision-making.

The analysis also identified a large difference at the moment of birth. Children from pregnancies reported as unwanted were 32.3 percentage points less likely to be delivered with skilled supervision. Skilled birth attendance means that a trained health professional, such as a midwife, nurse or doctor, is present and able to recognize complications and provide or arrange appropriate care. This can be critical when labor is obstructed, severe bleeding develops or a newborn needs immediate resuscitation. The result is particularly important because antenatal care and supervised delivery are connected stages of the same safety system: prenatal visits can prepare a mother for birth, while skilled attendance provides rapid intervention when complications arise. A reduction in supervised delivery does not mean that every child in an unwanted pregnancy experiences a dangerous birth, nor does it identify the precise service gap in any particular country. Rather, it indicates a population-level shift in the probability of receiving professional care, concentrated among the births whose pregnancy intentions were affected by previous sibling sex.

For children, the clearest nutritional signal was wasting. The study found that children born from pregnancies reported as unwanted were 11.8 percentage points more likely to be wasted. Wasting describes low weight relative to height and is commonly interpreted as an indicator of acute undernutrition, often associated with recent illness, inadequate food intake or both. It differs from stunting, which reflects impaired linear growth and typically develops through longer-term nutritional or health deficits, and from being underweight, which combines information about weight relative to age and can reflect either condition. The researchers examined all three indicators, but the instrumental-variable results highlighted wasting rather than showing a uniformly adverse effect across every measure. This distinction matters: the findings do not support the idea that unwanted pregnancy automatically produces every form of malnutrition. Instead, they point to a selected vulnerability that may arise through reduced healthcare contact, missed vaccinations, illness, feeding constraints or the diversion of household resources when a new child arrives in a family that did not intend another birth.

Vaccination results were more limited and varied by the child’s sex. In analyses separating boys and girls, the negative effects on antenatal care and skilled delivery appeared for both female and male children. Reduced vaccination coverage, however, reached statistical significance only among male children. The authors also tested child health outcomes including stunting, wasting and underweight, allowing them to examine whether the association was broad or concentrated in particular dimensions of health. Sex-specific differences should be interpreted carefully rather than treated as evidence of a universal biological effect. They may reflect differences in caregiving, disease exposure, healthcare-seeking behavior, social preferences or statistical precision across groups. The broader message is that family preferences surrounding the sex of children can influence reproductive timing and desired family size, while the consequences may then be distributed unevenly among children. In some communities, son preference or daughter preference can affect decisions about continuing childbearing, investment in care and the use of health services.

The study draws on Demographic and Health Survey data collected between 2011 and 2022, nationally structured surveys widely used to study reproductive, maternal and child health in low- and middle-income countries. Such surveys typically combine interviews with women of reproductive age, information about births and household characteristics, and measurements of children’s height and weight. The large sample permits comparisons across many settings and supports analyses adjusted for observable differences between families. The researchers also used World Bank data in their broader empirical framework, while the underlying survey data are available through the DHS Program. The scale of the dataset is a major strength, but cross-country evidence inevitably combines societies with different laws, health systems, cultural norms and definitions of access. Retrospective reports of pregnancy intention remain another limitation, even when instrumental variables are used. The estimates should therefore not be read as a fixed effect that applies equally to first births, second births or all unintended pregnancies worldwide.

The findings nevertheless carry a clear public-health implication: preventing unwanted pregnancies and ensuring that every pregnant person can obtain respectful, high-quality care are complementary strategies. Access to contraception, accurate reproductive information and confidential counseling can help people plan whether and when to have children, while strong maternal and child health services can protect families when pregnancies occur regardless of intention. The paper’s causal strategy strengthens the case that pregnancy intention is not merely a demographic label but may be connected to healthcare behavior and child wellbeing through social and household pathways. At the same time, the results should not be used to blame women or families for missed care. An unwanted pregnancy can occur in the presence of contraceptive failure, coercion, poverty, inadequate services or legal restrictions, and responsibility for reducing health risks rests heavily with health systems and social policy. By revealing measurable differences in antenatal visits, skilled delivery and child nutrition, the study turns a sensitive reproductive-health question into a broader warning about how family circumstances can shape medical care long after a pregnancy begins.

The implications of small-for-gestational-age pregnancies are profound, as they can lead to a variety of adverse outcomes for both the mother and the child. SGA pregnancies are often associated with placental insufficiency and fetal growth restriction, which can result in long-term health complications such as neurodevelopmental issues and chronic health conditions. Detecting these complications early through advanced imaging techniques like MRI could revolutionize prenatal care.

The study conducted by Xia et al. involved detailed quantitative analysis using MRI to assess both placental health and fetal brain development. The researchers aimed to establish a feasible methodology that could be reliably utilized in clinical settings. They sought to determine whether MRI might yield insights into the structure and function of the placenta and the developing brain, enabling healthcare professionals to make more informed decisions regarding the management of SGA pregnancies.

To carry out this significant research, advanced MRI techniques were employed, allowing for high-resolution images that provide detailed information about both the placenta and the fetal brain. This imaging modality offers several advantages over traditional ultrasound, including superior tissue contrast and the ability to visualize anatomical structures in more detail. These capabilities are crucial when evaluating conditions associated with SGA pregnancies, where the stakes are particularly high.

Moreover, the researchers emphasized the importance of quantitative metrics derived from MRI images in their analysis. By employing sophisticated image processing techniques and computer-aided quantitative analysis, the study sought to identify key indicators of placental health and fetal brain development. This quantitative approach enhances the objectivity of the assessments and could lead to more accurate predictions regarding the outcomes of SGA pregnancies.

An interesting aspect of the research is the potential of MRI to assess placental perfusion, which is a crucial factor for fetal development. Compromised blood flow to the placenta can severely impact nutrient and oxygen delivery to the fetus, which are essential for healthy growth. By quantifying placental perfusion via MRI, researchers could provide invaluable insights into the condition of the placenta and its capacity to support fetal development.

Another innovative aspect of this study is the examination of fetal brain development in conjunction with placental assessment. The intricate relationship between the placenta and fetal brain health has often been overlooked. By concurrently analyzing both elements, this study offers a more comprehensive understanding of how placental health can directly influence brain development in utero. This correlation is vital for future research aimed at identifying early interventions that could mitigate potential developmental deficiencies.

The findings from the study hold significant promise for clinical practice. If the feasibility of using MRI for quantifying placental and fetal brain parameters is validated through further research, it could lead to the incorporation of MRI into routine prenatal screenings for at-risk populations. This shift could facilitate earlier and more targeted interventions for those pregnancies deemed high-risk, thereby improving outcomes for both mother and child.

Additionally, the study highlights the challenges in distinguishing between normal variations and pathological conditions in placental and fetal brain development. Traditional assessment methods may not accurately capture subtle deviations that MRI could potentially identify. By employing advanced imaging techniques, healthcare providers could gain critical insights into the nuances of fetal health, fostering more tailored approaches to management.

The multidisciplinary nature of the study is another noteworthy aspect. The collaboration between radiologists, obstetricians, and pediatric neurologists exemplifies the importance of a cohesive approach to addressing complex issues in prenatal care. By integrating diverse expertise, the team was better positioned to address the multifaceted challenges presented by SGA pregnancies and enhance the overall quality of care provided to expectant mothers.

Another compelling dimension of the research is the potential for establishing normative data for placental and fetal brain development based on MRI assessments. As the researchers collect data from a broader cohort, they can develop benchmarks that clinicians can utilize to evaluate individual cases. This could be instrumental in creating standardized criteria for assessing healthy versus compromised pregnancies.

In summary, the pioneering research led by Xia et al. represents a significant stride toward enhancing our understanding of small-for-gestational-age pregnancies through the application of magnetic resonance imaging. By providing a dual focus on placental health and fetal brain development, the study rallies attention to the intricate connections between these vital aspects of prenatal health. This innovative approach not only underscores the beauty of interdisciplinary collaboration but also shines a light on the transformative potential of advanced imaging techniques in modern obstetrics.

As this research garners attention in the scientific community, the hope is that future studies will expand the knowledge base surrounding the role of placental health in fetal development. As we push the boundaries of what is known about pregnancy complications, the ultimate goal remains clear: to ensure healthier pregnancies and better outcomes for generations to come.

By harnessing cutting-edge imaging technologies and fostering collaboration among specialists, this study exemplifies the future of prenatal medicine—a future where informed decisions, early interventions, and profound understandings of fetal development are paramount in our quest to elevate maternal and child health.

Subject of Research: Quantitative analysis of placenta and fetal brain using MRI in small-for-gestational-age pregnancies.

Article Title: Magnetic resonance imaging based quantitative analysis of placenta and fetal brain in small-for-gestational-age pregnancies: a feasibility study.

Article References:

Xia, B., Jiang, L., Qian, Z. et al. Magnetic resonance imaging based quantitative analysis of placenta and fetal brain in small-for-gestational-age pregnancies: a feasibility study.
Pediatr Radiol (2025). https://doi.org/10.1007/s00247-025-06373-5

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s00247-025-06373-5

Keywords: MRI, placental health, fetal brain development, small-for-gestational-age pregnancies, prenatal care.