This is a very common problem. It would be difficult to recall a month in general practice in which a patient, who has recently had a baby or perhaps has married for a second time after having had children previously, hasn’t raised the same difficulty.

The vagina is a fibromuscular tube in which the walls are usually touching each other all the way along its length except at its upper end, where the cervix keeps them apart. Pregnancy inevitably stretches the vaginal walls and may well tear both its fibroelastic component and the muscle. If the tear is not repaired, or if the wall is only stretched and not torn, the woman is left with a less elastic and dilated vagina. As a result, it doesn’t grip the penis well and, therefore, doesn’t excite the penile nerve endings effectively. If the woman is unusually well lubricated, these difficulties are compounded.

Another factor that may interfere with a satisfactory sexual relationship is partial erectile dysfunction (partial impotence) from which the male may be suffering. Previously this dysfunction may have been disguised by the stimulation provided by a tight vagina but now it may have been revealed by its lax walls.

Episiotomy, a cut in the perineum during delivery to prevent it from tearing, also serves to prevent excessive stretching of the vaginal wall. It is controversial but in many, if not most, developed countries it is regarded as routine. A very slow and carefully managed delivery of the head may save the immediate tear and make life more comfortable in the week or two after delivery, but there may be pay-back time later when the sex drive returns.

Episiotomy, in some cases, may also be advantageous to the baby, but whatever the reason its repair needs experience. To say that all doctors are worried lest they sew the woman up so tightly that sex becomes impossible is an understatement. Despite their anxiety, it happens. Likewise, other women are repaired inadequately and are left with a perineum without the necessary muscle support behind it.

The third common complication is that, for some reason or another, the scar tissue is tender after healing. Research published in the early 1980s in the American Journal of Obstetrics and Gynaecology showed that 25 per cent of women had some degree of superficial dyspareunia (vaginal pain and tenderness during intercourse) after vaginal repair. This research was based on cases in which most had far more extensive repair than is usually necessitated by childbirth. After childbirth, and after healing if there has been an episiotomy, exercises may be helpful. Pelvic floor exercises are frequently prescribed and are so easy to carry out that some can be performed just about anywhere. They certainly won’t do any harm, but how successful they are has been questioned. What is certain is that exercises with vaginal weights tighten the vagina. The devices are kept in the vagina for increasing lengths of time. In extreme cases surgery can be useful to tighten the vagina, but the disadvantages of this are similar to those of an episiotomy.

However, different positions for sex may help your husband. The missionary position doesn’t put so much pressure on the penis because in this position it fits most easily, like two pieces of a jigsaw. If one bit of the jigsaw doesn’t slot in easily, the friction will be that much greater. The standard advice is that vaginal sex in the doggie position puts more pressure on the penis than missionaries ever enjoyed.

If my own experience is anything to go by, pregnancy involves a constant stream of badgering about Dr Arnold Kegel and his pelvic-floor exercises (the rhythmic clenching and unclenching of the pubococcygeal, PC, muscles). I recall bright-eyed and bushy-tailed midwives encouraging me to “do them while I was waiting for the bus”, and junior doctors who looked too young to have ventured beyond tonsil-hockey earnestly stressing the importance of staying “honeymoon fresh”. And the only time I ever saw a gynaecologist, I was warned that in nine months’ time I would push out both my baby and my sex life if I didn’t “Kegel” 50 times a day.

It was great advice and I’ve no doubt that the exercises work but, well, we’re not very good at preventive measures are we? I mean, if we were, the birth rate would go right down, wouldn’t it? And none of us would ever need to go on a diet, or pay a parking fine, or take a hangover cure.

Despite being fully informed as to what is good or right, we still tend to do what we want. And a pregnant woman with two screaming toddlers doesn’t generally “want” to stand at a bus stop trying to squeeze a lemon with her genitals. Besides which, by the time she feels her pelvic muscles giving up the ghost she has vowed never to have sex again anyway. Sick and tired of being preached to by medics, midwives and mothers-in-law, she gives Dr Kegel the intellectual finger and eats another cream bun.

It is only when her brain cells have resumed normal function and her shell-shocked body has had a full night’s sleep that her dormant libido begins to yawn and stretch and flex its wasted muscle.

At that point Dr Kegel laughs in his grave and says “I told you so”, while she scribbles a message to “PC” on a Post-it Note and sticks it on the fridge beside the diet plan and the penalty notice for the unpaid parking fines.

One month of clench and release 50 times a day should make a real difference. You should get your husband to do them, too, because as men age their testosterone level shrivels and so does everything else (www.bringhealth.com/kegel_exercise.html).

If you don’t feel any improvement, you might want to invest in a pelvic toner (£29.99 plus p&p from www.natural-woman.com). It looks like a cross between a vibrator and a set of curling tongs and the idea is that you slather it with lubricant, insert it and squeeze your PC muscles to bring the two sides together.

Alternatively, you could try Betty Dodson’s Vaginal Barbell ($69.95; www.bettydodson.com/barbellinfo.htm). Dodson is a renowned sexologist and her stainless steel barbell is apparently “sturdy enough to become a family heirloom that can be passed down from grandmother to granddaughter”. The mind boggles. The barbell is 6in long, natch, weighs nearly 1lb (0.45kg) and is inserted into the vagina so that you can bench- press your PC muscles around it.

If home helps don’t work, you should talk to your GP. He or she may suggest options such as “neuromuscular electrical stimulation” (probe, electric current, vagina, muscle contraction, etc) or “magnetic field treatment” (chair, magnets, vagina, your guess is as good as mine). As a last resort, you could always buy yourself a “designer vagina”. It’s an expensive and painful option that is likely to put you off sex for years. Which makes it a bit like childbirth really.

Over to you

Do you have a sexual dilemma for Suzi Godson and Dr Thomas Stuttaford? Send your e-mails to body&soul@thetimes.co.uk or write to Body&Soul, The Times, 1 Pennington Street, London E98 1TT. The authors regret that, although your letters are much appreciated, they cannot respond personally.