Medical officials say 40 percent of children in Iran are born by C-section on average, but the percentage in Tehran is as high as one in every two deliveries -- and it is greater than 60 percent in Isfahan and Gilan provinces.
"The World Health Organisation recommends a Caesarean section rate of 10 to 15 percent," said gynaecologist Nasrin Changizi, who heads the mothers' health bureau in the Iranian health ministry.
Shirin, a secretary in a construction company, said it was the thought of the pain during labour and the damage she feared could be inflicted on her body that encouraged her to choose a "planned" delivery.
"Why shouldn't I enjoy the benefits of science when it is available?" she asked in a Tehran clinic, as she waited along with a dozen other women to have a colour 3-D ultrasound of her baby.
All but one of the mothers-to-be were going to have a Caesarean section.
Shirin will spend 15 million rials (1,600 dollars, 1,130 euros) on the procedure and hospital expenses, and her health insurance will cover only two million rials (215 dollars) of that.
The rest will have to come from family savings. "But it is worth it," she said.
Changizi said Iranian women were not generally well-informed about the benefits and risks involved with each form of childbirth, and that an elective C-section potentially had more side effects than having a baby the natural way.
"It is crucial to have a beautiful experience to promote normal vaginal delivery," she told AFP, but also conceded that some women were put off by the thought.
Doctors concerned about the health of both mother and child are quick to end the natural process at the slightest sign of complications. They may also be concerned about facing malpractice complaints, Changizi said.
She added that many doctors were unwilling to deliver babies the natural way because of the long hours women can spend in labour -- and also the significant difference between fees for a C-section and natural childbirth.
Shabnam's friends and cousins told her she was out of her mind when she announced she wanted to give birth naturally.
The 27-year-old, who is due in three months, said she was lucky to find a good doctor who did not frown at her choice, even though her own mother disagrees with her decision.
"I want a painless delivery but three doctors turned me down politely," she said. One Tehran obstetrician told her he did not believe in natural birth, insisting that Caesarean-born babies were smarter.
Shabnam's delivery, in which she will have an epidural anaesthetic, will cost about the same as a C-section. She has chosen to have her baby this way despite the widely held view that natural childbirth is for poor people only.
Doctor Pooran Hajian says it is basically the pain that scares women off natural birth, but that there are downsides associated with both methods of delivery.
"To me it makes no difference. If the mother's pelvis is appropriate I suggest natural birth, but 99 percent of my patients want a C-section."
She said if health officials sought to promote painless deliveries and offered this in state hospitals, which charge very little or nothing, more women would be willing to try it and the word would spread.
Iran prides itself on good family planning and maternal health. Officials say the maternal mortality rate was 24.6 per 100,000 live births in 2005 -- compared with nine in developed nations and 160 in western Asia.
Doctors and midwives perform 94 to 96 percent of deliveries in Iran.
But alarmed by the number of Caesarean births carried out when not medically necessary, Iran plans to reduce C-section rates to 20 to 25 percent of uncomplicated births by 2013.
Health officials have begun offering retraining workshops for obstetricians to promote physiological birth with minimum intervention and without inducing birth.
They also advocate more responsibility and better pay for midwives to monitor women in labour in order to spare doctors from having to spend long hours at their patients' bedsides.
Maternity classes have been introduced in a number of hospitals where pregnant women learn about pain control, special breathing techniques and muscle relaxation.
"When a mother is taught to control fear, labour pains can be controlled or reduced without medication," Changizi said.
She said state media, as well as schools and universities, needed to better educate women about childbirth and the benefits and hazards involved in their choice of how their babies are delivered.
"Women are concerned about pelvic relaxation in natural delivery, but they overlook the side effects of a Caesarean," she said. "We want doctors to give the mother all the information and then let her choose."