The main causes of<unk>  include: a large or abnormally positioned baby, a small pelvis, and problems with the birth canal. Both the size and the position of the fetus can lead to<unk> . Abnormal positioning includes shoulder dystocia where the anterior shoulder does not pass easily below the pubic bone. A small pelvis of the mother can be a result of many factors. Risk factors for a small pelvis include malnutrition and a lack of exposure to sunlight causing vitamin D deficiency. A deficiency in calcium can also result in a small pelvis as the structures of the pelvic bones will be weak due to the lack of calcium. A relationship between maternal height and pelvis size is present and can be used to predict the possibility of<unk> . This relationship is a result of the mother's nutritional health throughout her life leading up to childbirth. Younger mothers are also at more risk for<unk>  due to growth of the pelvis not being completed. Problems with the birth canal include a narrow vagina and perineum which may be due to female genital mutilation or tumors. All of these factors lead to a failure in the progress of<unk> . Evolution<unk>  is more common in humans than any other species and continues to be a main cause of birth complications today. Modern humans have morphologically evolved to survive as bipeds, however, bipedalism has resulted in skeletal changes that have consequently narrowed the pelvis and the birth canal. The combination of increased brain size and changes in pelvic structure are the major contributors of<unk>  in modern humans. It is also common for<unk>  in humans to be caused by the fetus’ broad shoulders. However, morphological shifts in pelvic structure still account for the inability of a fetus to effectively pass through the birth canal without major complications Other primates have a wider and straighter birth canal that allows a fetus to pass through more effectively. Mismatch between birth canal size and infant cranial width and length due to bipedal locomotion requirements have often been referred to as the obstetric dilemma, since compared to other great apes, modern humans have the greatest disproportion between infant cranial size and birth canal size. Shrinking of upper extremities and curvature of the spine have also affected the way modern humans give birth. Quadruped apes have longer upper limbs that allow them to reach down and pull their fetus out of the birth canal unassisted. Other primates also have a wider and straighter birth canal that allows a fetus to pass through more effectively. Modern human’s shorter upper extremities and evolution of bipedal locomotion may have placed a premium on assistance during<unk> . For this reason, researchers argue that assisted<unk>  may have evolved with bipedalism.<unk>  has been documented as a complication of childbirth since the field of obstetrics originated. For over 1,000 years obstetricians have had to forcibly remove<unk>  fetuses to prevent the death of the mother. Prior to the existence of the cesarean section, fetuses that were<unk>  had a low survival rate. Even in the 21st century, if<unk>  is left untreated, it could result in mother and infant death. Although surgical removal of the fetus is the preferred method of managing<unk> , manual removal using medical tools is also common.<unk>  is unique to humans compared to other primates. The evolution of humans to become obligate bipedal and increase in brain size create the problems associated with<unk> . In order for bipedal locomotion to be possible, many changes had to occur to the skeletal structure of humans, especially in the pelvis. Both the shape and orientation of the pelvis changed. Other primates have straighter and wider pelvises compared to humans. A narrow pelvis is better for bipedal locomotion but makes childbirth more difficult. The pelvis is sexually dimorphic, with females having a wider pelvis to be better suited for childbirth. However, the female pelvis still must accommodate for bipedal locomotion which is what creates the challenges for<unk> . The brain size of humans has also increased as the species has evolved, resulting in a larger head of the fetus that must exit the womb. This requires human infants to be born less developed when compared to other species. The bones of the skull are not yet fused when a human infant is born in order to prevent the head from becoming too large to exit the womb. However, the head of the fetus is still large and poses the possibility for<unk> .
Obstructed labour
Prolonged labor
Septic abortion
Prelabor rupture of membranes
Toxic abortion
Unsafe abortion
Uterine rupture
Recurrent miscarriage