Pregnancy is a period of time during which a fertilized egg develops into a fetus inside a woman's uterus. It is a complex process that involves various physiological changes in a woman's body. These changes are necessary to support the growth and development of the fetus. The most notable changes and adaptations that take place during pregnancy include elevated resting heart rate, elevated cardiac output, and decreased peripheral vascular resistance (1, 2). An increase in endothelium-dependent vasodilation appears to be a major moderator of these modifications and adaptations. Nitric oxide (NO) released by endothelial cells has been suggested to be the primary cause of the reduced systemic vascular resistance seen during pregnancy. Sustaining appropriate placental blood perfusion requires the uterine arteries' high exhaustion and low resistance (3). However, as the pregnancy progresses, the resistance of uterine spiral artery blood flow will be decreased gradually, the V-shaped notch in early diastole tends to be flat and even disappear in late pregnancy (4). This in turn results in a decreased production or an increased inactivation of NO that would be linked to the endothelial dysfunction and reduced placental perfusion. If the endothelial and placental function becomes impaired, it will cause various obstetric disorders such as intrauterine growth restriction, hypertensive disorder of pregnancy, gestational diabetes mellitus, spiral arterial embolism, decidual necrosis, placental abruption, preterm labor; leading to adverse pregnancy outcomes such as perinatal morbidity and mortality globally (5, 6).
Therefore, even though motherhood is a positive and enjoyable experience, it is also a vulnerable period that can be accompanied by various complications in which many women are experiencing suffering, illness, and death. Hypertensive disorders of pregnancy (HDP) are one of the most significant contributors to these complications and sufferings. Maternal hypertensive disorder is a group of high blood pressure disorders that include gestational hypertension, preeclampsia, eclampsia, preeclampsia superimposed on chronic hypertension, and chronic hypertension (7). The development of hypertensive disorders is thought to be due to various factors, including genetic predisposition, immunological factors, and abnormalities in the placenta. The exact mechanism is not fully understood, but some of commonly observed factors are placental imbalance, abnormal immune response, genetic factors, and endothelial dysfunction.
HDP is mainly manifested as hypertension and damage to important organs such as heart, kidney, liver and nervous system. The previous study has proven 16% of maternal deaths can be attributed to HDP, so it has become an urgent obstetric crisis (8). Hypertension in pregnancy is associated with potentially lethal complications including abruption placentae, disseminated intravascular coagulation, cerebral hemorrhage, hepatic failure, and acute renal failure (9). Worldwide, hypertensive disorders remain the leading causes of pregnancy- related maternal mortality, stillbirth, and neonatal death (10).
In addition to hemodynamic adaptive changes, pregnancy is also characterized by endocrine and metabolism changes thereby forming a pseudo-diabetic state of progressive insulin resistance. In the early stages of pregnancy, there is an increase in insulin sensitivity. This is because the body needs to provide adequate energy and nutrients to support the growing fetus. Insulin sensitivity is enhanced to ensure that glucose from the mother's blood can be transported to the placenta and reach the developing baby. However, as pregnancy progresses, especially during the second and third trimesters, there is a natural decrease in insulin sensitivity. This is primarily due to the presence of hormones like estrogen, progesterone, and human placental lactogen, which can interfere with insulin action (11, 12). The decrease in insulin sensitivity during pregnancy is a normal physiological response. It allows for the efficient utilization of glucose by the developing fetus, as it ensures that glucose is available for fetal growth and development. However, if the mother failed to manage this change appropriately the decrease in insulin sensitivity can become too significant, resulting in the development of gestational diabetes mellitus (GDM) which is one of the most common complications related to pregnancy.
GDM is a condition characterized by high blood sugar levels during pregnancy. This condition affects approximately 14% worldwide (13), leading to adverse maternal and neonatal outcomes. It typically resolves after delivery, but it can have both short- and long-term potential risks for both the mother and the baby if not managed properly. Jaundice, birth trauma, erythremia, hypoglycemia, macrosomia, and hypocalcemia are examples of unfavourable newborn outcomes. Comparing the children of euglycemic women to those of gestational diabetic moms, the latter group is more likely to experience obesity, impaired glucose tolerance, and diabetes in adolescence or early adulthood. Moreover, mother with GDM have a higher chance of developing overt diabetes following childbirth and a higher risk of developing other pregnancy problems such preeclampsia, infection, and postpartum hemorrhage (14–16).
Therefore, GDM and HDP are common complications that can significantly impact the health of the mother and the unborn baby, in which their incidence become rise in recent years, making them a significant public health concern. In order to prevent these and other life threating complication of pregnancy and their subsequent deadly consequence many scholars recommend different medical and non-medical preventive strategies. Among these strategies some of them are community engagement and mobilization, food security for girls and pregnant women, delayed marriage and delayed first pregnancy, birth spacing, health human resources, screening for HDP and GDM risk, provision of antenatal care, time-of-disease maternal risk assessment, time-of-disease fetal risk assessment, well-resourced settings, and physical activities (10). So, as researches indicated physical activity during pregnancy may have a positive effect in reducing the risk of developing GDM and HDP.
Physical activity is any bodily movement produced by skeletal muscles that require energy expenditure. It is all types of movement include walking, cycling, wheeling, sports, and active recreation and play, and can be done at any level of skill and for enjoyment by everybody. Engaging in regular physical activity offers numerous benefits for both physical and mental health. The benefits of physical activity among men and non-pregnant women on health, such as reducing the risk of essential hypertension, coronary atherosclerotic heart disease, and type 2 diabetes are well documented, but there is a gap on the effect of physical activity during pregnancy on pregnancy related complication (17).
There has been a controversy about exercising during pregnancy. On one side, there are those who argue that exercise during pregnancy can have numerous benefits for both the mother and the baby. They suggest that staying physically active can help reduce the risks of gestational diabetes, preeclampsia, excessive weight gain, and other complications during pregnancy. Additionally, regular exercise is believed to boost mood, improve energy levels, and promote better sleep for expectant mothers. It is worth noting that the American College of Obstetricians and Gynecologists (ACOG) recommends moderate-intensity physical activity for most pregnant women, provided they have no medical or obstetric complications. They emphasize that exercises like walking, swimming, and low-impact aerobics are generally safe during pregnancy, but it is crucial for expectant mothers to consult with their healthcare providers before starting or modifying an exercise routine. WHO is also recommended that pregnant women engage in at least 150 minutes of moderate-intensity aerobic activity spread throughout the week (18–20).
On the other side, some experts assert that pregnant women should limit their physical activity and avoid excessive exertion. They express concerns about potential risks to the developing fetus, such as an increased likelihood of preterm labor, reduced blood flow to the uterus, and overheating. Critics of exercise during pregnancy argue that caution should be taken, especially if there are underlying health conditions or pregnancy complications present. For this reason, many pregnant women are physically inactive, increasing this inactivity during the last trimester of pregnancy (13, 21). Therefore, this study would provide additional knowledge in order to decide whether or not exercising during pregnancy.
The main objective of this study is to assess the effect of level of physical activities during pregnancy on the development of HDP and GDM. This study is not only significant for the field of obstetrics and gynecology but also for pregnant women and health professionals involved in antenatal care and public health policymakers. It aims to address a critical research gap and provide evidence-based recommendations that can inform clinical practice and prenatal care guidelines. The findings of this research have the potential to impact the lives of pregnant women and their unborn babies by promoting a healthy lifestyle and reducing the risk of complications during pregnancy.