A sharp drop in the number of men undergoing NHS vasectomies in England could be linked to a recent increase in abortions among older women, experts have said.
Over the last decade the NHS has seen a fall of more than 50% in the procedure, according to data from the NHS Information Centre and Hospital Episodes Statistics published by the British Pregnancy Advisory Service (Bpas).
In 2001/02 there were 37,700 vasectomies performed, compared to 15,106 in 2011/12. This year's figures also represented a 16% decline from 2010/2011.
Researchers from Bpas said the declining number, which does not include those carried out at private clinics, could be prompted by a number of factors, including restrictions on funding or greater emphasis on contraceptives for women such as hormonal and copper coils.
Men may have reservations about committing to the "snip", one of the most effective forms of contraception, because of an increasing awareness that a relationship may break down, amid the rise of second families.
It could also explain a recent increase in abortion rates among older women over 30, which have risen 10% in the last decade, Bpas added.
Ann Furedi, chief executive of Bpas, said: "Vasectomy is a safe and reliable method that gives men the opportunity to play an active role in contraception. It is disappointing that the only long term method which enables men to play this part is declining.
"We must ensure that all couples who want to use this method can access it promptly on the NHS, while recognising that it won't be for everyone.
"Creating more choice is vital. We sincerely hope that the research into creating a reversible male contraceptive that is currently under way results in a method that will have a real impact on the involvement of men in family planning."
Countries with a low rate of vasectomy, such as France where the procedure was banned until 1999 and remains uncommon, have a relatively high rate of abortion amongst older women.
England has historically had a high vasectomy rate, with around 16% of the male population under 70 having undergone the procedure, and a lower abortion rate among older women.