What is a key function of relaxin during pregnancy in dogs?

Relaxin is a hormone that plays a crucial role during pregnancy, particularly during the process of parturition, which is the act of giving birth. It is produced by the ovaries and placenta and serves several important functions in preparation for delivery. One of the primary actions of relaxin is to help relax and soften the connective tissues, particularly in the pelvic region, which allows for the expansion of the birth canal. This softening process is essential for facilitating easier passage of the puppies during birth.

In addition to its effects on the pelvic area, relaxin also helps to inhibit uterine contractions before labor begins, which is important to maintain a stable environment for the developing fetuses throughout the pregnancy. As the time for parturition approaches, the levels of relaxin increase, preparing the body for the physical demands of labor. Thus, facilitating parturition is a key function of relaxin in pregnant dogs.

Other options, while they may seem relevant, do not accurately describe the primary role of relaxin in pregnancy. For example, while appetite and weight gain may fluctuate during pregnancy, they are not directly influenced by relaxin. Similarly, fetal growth is primarily driven by other hormones and nutrient supply rather than relaxin itself.