(CNN) -- Six weeks after Robyn Roark gave birth to her first child, her doctor told her that she could start having sex again. She started crying.
"I could not believe that just six weeks after having a baby, that that would even be something to consider," said Roark, 32, of the San Francisco, California, area. "I could barely figure out how to shower and eat. How could I possibly start having sex?"
Roark, who writes for the Silicon Valley Moms Blog, isn't alone. Although doctors say it's physically OK to have sex around six weeks after the birth of a child, some mothers, such as Roark, say they feel so fatigued and overwhelmed that they put sex on the back burner for months, or even a year, after a doctor clears them for physical activity.
Why it's a problem
Besides exhaustion, there are biological reasons why some women don't return to their previous sex lives after childbirth, said Dr. Irwin Goldstein, director of sexual medicine at Alvarado Hospital in San Diego, California. Testosterone goes down for some women after the delivery, and breast-feeding releases the hormone prolactin, which inhibits arousal.
While Viagra has been a popular remedy for men with low sex drive, there is no medical treatment on the market for female sexual dysfunction, despite the number of women who are unable to resume their pre-childbirth intimacy levels. A drug called Flibanserin, currently under Food and Drug Administration review, could be available as soon as this year and would treat chemical imbalances that impede a mother's sexual desire, Goldstein said.
New mothers may also be reluctant in bed because of physical discomfort or because they have some element of postpartum depression, said Dr. Rini Ratan, assistant clinical professor of obstetrics and gynecology at Columbia University Medical Center.
The first six months after delivering her son were the hardest for Roark, as she struggled to figure out the balance between taking care of her newborn and having time for her own needs as basic as showering. As for sex, it took about a year for her and her husband to find their groove again, and for her to enjoy sex, she said.
"There were times where I literally made grocery lists in my head" during sex, said Roark, whose son is now nearly 6 years old. "It wasn't horrible, I just wasn't always in the right frame of mind."
New mothers' sexual experiences vary widely -- some actually don't have a decreased libido and want to have sex again right away, Ratan said.
"For me, I was looking forward to it because it brought me back to the person I was before," said Kristen Chase of Atlanta, Georgia. Chase, a mother of three, is a sex columnist and author of the blog "Mominatrix."
How complicated the pregnancy was, and whether the mother has had children before, may factor into how she feels about physical intimacy after the birth, Ratan said.
For some women, it doesn't get easier with more children. Julie Marsh, 38, needed a full year after the births of each of her three children to get her sex life back to normal.
A newborn needs to be in contact with its mother constantly, and during those moments when the mother gets a break, she often just wants to be left alone, Marsh said.
"The last thing you want, when it's no longer in contact with you, the last thing you want is for anyone else to touch you," she said.
The dad perspective
With two children -- ages 18 months and 3.5 years -- Peter Renton, 44, of Denver, Colorado, doesn't feel as if he and his wife have gotten back to the sex life they had before they became parents. Six weeks after the first birth, Renton was ready to get back into the sack, but it was a different story for his wife.
Both births were complicated. The first was an emergency cesarean section after a 28-hour labor. The second was a vaginal birth after a C-section, which carried the risk of uterine rupture; Renton described the delivery as "challenging." As a result, Renton's wife tells him, her body still has not recovered, and sex is somewhat painful. There's also the issue of finding time for physical intimacy with two very young children in the house.
"You've just got to know that at any moment, if you're at home and you're having sex, you could be interrupted," he said. "You've got to be a little bit more flexible. It can lead to some disappointment sometimes."
Still, the couple is trying to get into a habit of having sex twice a week, he said.
What to do
Every day, Goldstein sees female patients who believe there is something wrong with them because they don't look forward to sex the way they used to, even two or three years after their first child is born.
It's natural to refrain from sex just after a child is born, but persistent sexual problems can cause distress in the relationship, Goldstein said. When one partner has a high interest in sex and the other's desire stays low, seeing a counselor or sex therapist may be the best course of action, he said.
The therapist would focus on the problems the couple is having and examine how to regain confidence in the relationship, he said. If a drug for female sexual dysfunction becomes available, this would also help many women.
For those whose problem hasn't reached that stage, parents have a slew of tips.
Chase recommends having scheduled "date nights" that allow a couple to leave their children with a baby sitter and get out of the house. As for the vaginal dryness that comes with breast-feeding, a good lubricant "can change people's lives," she said.
Renton and his wife enjoy weekends away from the kids when they take occasional trips to other cities, he said. These weekends are important to their relationship, he said.
Mothers should take advantage of any moment that they do feel in the mood for physical intimacy, as those moments are fleeting, Roark said.
"The more kids you have, the fewer opportunities you have to have sex," Marsh said. "You've got to make the most of what you've got when you've got it."
A new mother's spouse or partner should do things that make her happy, as simple as picking up stray socks or looking after the kids, Marsh said. These gestures can help an exhausted mother feel loving toward her partner.
Despite the difficulties after the birth of their first son, Roark and her husband decided to have a second child, whom Roark will give birth to in the fall. She feels better prepared for childbirth this time around and is prepared for the "slump" in sex.
In retrospect, she wishes that last time she had been a more willing partner in bed -- both she and her husband would have been happier just from hugging and kissing, she said.
"When each person is trying to make their partner satisfied, whether that's emotionally or physically, everyone ends up benefiting from that," she said.