All your petting zoo favorites are at the Great American Petting Zoo presented by the Maricopa County Fair! Stop by the Cattle Barn for the entire run of the Arizona State Fair and check out ducks, llamas, donkeys, deer, chickens, pigs, and the Australian wallaby. Included with Arizona State Fair admission.
After ovulation estrogen is joined by progesterone from the corpus luteum making the endometrium denser and mature. Estrogen is not only metabolized by the liver but also re-circulated between the gut and the liver (entero-hepatic circulation). Antibiotics can affect estrogen metabolism in two ways. Most antibiotics are metabolized in the liver and their presence can affect the rate of metabolism of estrogen (and progesterone). This can change the supply of estrogen available in the blood and that can cause irregularity of the cycle. Some antibiotics cause diarrhea like symptoms as they change the gut flora.
The most dramatic rise in progesterone levels happens between the ninth and 32nd weeks of pregnancy, which means constipation is most likely to start any time during this these weeks. Another cause of constipation is the increased size of the uterus, which puts pressure on the bowels. As your uterus grows larger, so does the chance you will suffer from constipation, but constipation caused by pressure on the bowels doesn't usually occur until the later stages of pregnancy.