Oh, the joys of pregnancy. The exhaustion, the weight gain, the queasy tummy and frequent trips to the bathroom…and that’s just daddy-to-be.

Everyone knows hormones are involved in a woman’s pregnancy. They are the ones that get the pregnancy going, the ones that keep the pregnancy interesting, and the ones that bring on the labor. Hormones get blamed for sleepless nights, ice cream and pickle cravings, and tears at someone not landing a deal on Shark Tank. But did you know that men experience similar ups and downs of their hormone levels when involved in a pregnancy?

The medical term for when a man suffers symptoms related to pregnancy is called the Couvade Syndrome. Couvade comes from the french word couvee, meaning “to hatch.” Today, it has come to mean a man is having a “sympathetic pregnancy.” Many people thought that a man’s symptoms were all in his head, a reaction to the stress of impending fatherhood or a bid for sympathy. Not so, say researchers. Approximately 90 percent of men experience at least one pregnancy-related symptom, sometimes severe enough to seek medical attention. More than 20 percent of men with pregnant partners sought care for symptoms that “couldn’t be objectively explained,” reports the Annals of Internal Medicine. Researchers began to explore the idea that hormones were causing some of the symptoms, and their studies seem to find the truth in that assumption.

Endocrinologist Katherine Wynne-Edwards and her colleagues of Queen’s University recruited 33 couples from childbirth classes to participate in her observations of daddy hormones. The participants were observed, interviewed and tested for several weeks prior to and just after the birth of their babies. Hormone levels were charted using a saliva swab method, which let the researchers test more than previous blood tests studies.

Researchers discovered some interesting observations during the study of pregnancy hormones in expectant fathers. The study followed and observed the rising and falling of hormones in men during their partner’s pregnancy. Hormones including testosterone, estrogen, prolactin, and cortisol.

Testosterone is no stranger to most men and women. It is talked about all the time and blamed for many unexplained actions of men. Testosterone is blamed for fights over football, joyriding and teenagers doing wild stunts. Linked with competitiveness, testosterone levels actually rise in males in response to winning sporting events and other competitions. Its production changes in response to behaviors that most men experience such as intercourse, sports, and work successes and can send it spiraling upward. This hormone is crucial to winning the mating game and gets the procreation started. Once the baby is born; however, the testosterone levels in men drop sharply.

Psychologist Anne Storey found a 33 percent drop in testosterone in men during the first three weeks of the baby’s life. The levels returned to normal by the time the infant was between four and seven weeks old. This change or dip in levels is thought to promote bonding by setting in motion the more cooperative, less competitive enterprise of parenting. Ross Parke, a psychologist at the University of California at Riverside, thinks that the drop in testosterone may “let the nurturing side of men come to center stage.”

The next hormone, estrogen was studied by Wynne-Edwards and graduate student Sandra Berg in a follow up study. They found that in addition to the rise and fall of testosterone levels, estrogen increased 30 days before birth and continued for the whole 12 weeks of testing after the birth. While men do have low levels of estrogen naturally, higher levels of estrogen can induce more nurturing behavior in males. This might offer some insight as to why your manly husband tears up while watching reruns of old movies during your third trimester. “Male and female brains are remarkably similar,” Wayne-Edwards points out. She theorizes that the similarities between the mail and female brains might be linked by hormones.

The third hormone to examine is prolactin, which gets its name from the role it plays in producing lactation in women. Prolactin happens to be the hormone we produce when we fall in love. It also instigates parental behavior in animals. Researchers Storey and Wynne-Edwards found that prolactin rose by approximately 20 percent in men during the three weeks after their partner gave birth. Prolactin levels in men who experience pregnancy symptoms were significantly higher as well.

The final hormone is cortisol, the so-called “fight or flight” hormone. Wynee-Edwards and Storey explains that cortisol may better be called a “heads up, eyes forward, something really important is happening” hormone with regard to pregnancy and birth. Cortisol levels naturally increase in women during pregnancy. In fact, a cumulative rise in stress hormone levels sets off labor and delivery.

Mothers with high levels of cortisol can detect their baby by scent more easily than a mother with low levels. Higher cortisol level mothers also respond more sympathetically to their infants’ cries and describe their relationship with their infants more positively, too.

Could the sights, sounds and smells of a newborn affect hormones? During one part of the study, the researchers had couples hold a doll that hand been wrapped in a receiving blanket used by a newborn within the preceding 24 hours. They listened to a tape of a real newborn crying for six minutes and then watched a video of a newborn struggling to breastfeed. The investigators took blood from the men and women before and after the test and discovered something startling: Men who expressed the greatest desire to comfort a crying baby had the highest prolactin levels and the greatest reduction in testosterone. Testosterone levels plummeted in the men who held the doll for a full half-hour.

Scientists are thinking that hormones stimulate more neuron connections in the part of the brain responsible for nurturing, or cause the neurons to fire more quickly.

A man’s hormones may play an important role in helping him experience the full range of emotions with regard to becoming a new father. They may help him develop stronger bonds and become more devoted and loving with his child.

The good news is that when daddy-to-be is complaining about the mood swings or feeling nauseous, it may be a sign that his hormone levels are encouraging him to be a good, committed father. Pass him the ice cream and pickles, please!