Mighty Dons Of Science News

Birth con­trol pills may al­ter wom­en’s abil­i­ties to choose, com­pete for and re­tain mates, a new re­port suggests.

The pa­per pub­lished on­line on Oct. 7 in the re­search jour­nal Trends in Ecol­o­gy and Ev­o­lu­tion re­views emerg­ing ev­i­dence that oral con­tra­cep­tives af­fect these ac­ti­vi­ties by dis­tort­ing nat­u­ral hor­mo­nal cy­cles.

Wom­en are fer­tile briefly dur­ing their men­stru­al cy­cle, just be­fore ovula­t­ion. Stud­ies have found that both sex­es’ part­ner pref­er­ences vary ac­cord­ing to pre­dict­a­ble hor­mo­nal fluctua­t­ions as­so­ci­at­ed with this cy­cle. Ovu­lat­ing wom­en pre­fer more mas­cu­line, dom­i­nant and com­pet­i­tive males, as well as males more ge­net­ic­ally un­like them­selves. Mean­while men, some stud­ies sug­gest, de­tect wom­en’s fer­til­ity sta­tus, pre­ferring ovu­lat­ing wom­en in situa­t­ions where they can com­pare dif­fer­ent wom­en’s attrac­tiveness.

Con­tra­cep­tive pills al­ter the hor­mo­nal fluctua­t­ions as­so­ci­at­ed men­stru­al cy­cles and es­sen­tially mim­ic the more steady hor­mo­nal con­di­tions as­so­ci­at­ed with preg­nan­cy, ac­cord­ing to re­search­ers. “Lit­tle ef­fort has been in­vested in un­der­stand­ing the con­se­quences” of this, said study au­thor Al­ex­an­dra Alvergne of the De­part­ment of An­i­mal and Plant Sci­ences at the Un­ivers­ity of Shef­field, U.K.

Alverne and col­league Virpi Lumma re­viewed re­cent stud­ies sug­gesting use of the pill dis­rupts wom­en’s varia­t­ion in mate pref­er­ences across their men­stru­al cy­cle. The au­thors spec­u­lat­ed that the use of the pill may al­so in­flu­ence a wom­an’s abil­ity to at­tract a mate by re­duc­ing attrac­tiveness to men.

In­ter­est­ing­, wom­en on the pill don’t show the ovula­t­ion-specific at­traction to ge­net­ic­ally un­like part­ners, said Lum­maa. “The ul­ti­mate out­stand­ing ev­o­lu­tion­ary ques­tion con­cerns wheth­er the use of oral con­tra­cep­tives when mak­ing mat­ing de­ci­sions can have long-term con­se­quenc­es on the abil­ity of cou­ples to re­pro­duce.”

Tak­en to­geth­er, a grow­ing num­ber of stud­ies sug­gest the pill is likely to af­fect mat­ing de­ci­sions and thus re­pro­duc­tion, she added. “If this is the case, pill use will have im­plica­t­ions for both cur­rent and fu­ture genera­t­ions, and we hope that our re­view will stim­u­late fur­ther re­search.”