In essence, a pregnancy is pretty much characterized by high levels of hormones. And those hormones include Estrogen and Progesterone. Yes, the same hormones that play such a huge role in your menstrual cycle play an even bigger role during pregnancy. For instance, rising Progesterone helps prepare and maintain the lining of your uterus to home a fertilized egg in the early weeks of pregnancy. But it’s also partly why you’re more likely to live with bloating, digestive issues and cravings. Increasing levels of Estrogen, meanwhile, are actually produced by your placenta. They trigger organ growth, keep your uterus healthy and even get your boobs ready for potential breastfeeding. But they can also increase allergic reactions and cause dry, itchy patches of skin.