Timing of sex fact file

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The Fertility Coalition
Last updated September 2014

Timing and fertility – a fact file

Knowledge about the ‘fertile window’ is low among Australians of reproductive age

  •  Two  thirds  of  Australians  have  inadequate  knowledge  about  the  time  in  the  menstrual  cycle  when  a   woman  is  most  likely  to  conceive.
  • Many  women  are  unaware  of  when  they  ovulate.
  • Accurately-­‐timed  intercourse  can  reduce  time-­‐to-­‐pregnancy  and  help  avoid  unnecessary  IVF   treatment.
  • Recommending  sexual  intercourse  every  2  to  3  days  can  help  those  who  are  not  aware  of  the  ‘fertile   window’  optimize  their  chance  of  conceiving.

What is the ‘fertile window’?

  • Conception  is  only  possible  from  about  5  days  before  ovulation  through  to  the  day  of  ovulation.   These  six  days  is  the  ‘fertile  window’  in  a  woman’s  cycle  and  reflect  the  lifespan  of  sperm  (5  days)   and  the  lifespan  of  the  ovum  (24  hours).
  • The  ‘fertile  window’  depends  on  the  length  of  a  woman’s  cycle.  The  time  from  ovulation  to  the  next   period  is  about  14  days,  irrespective  of  cycle  length.  The  time  before  ovulation  varies  between   women.
  • The  likelihood  of  conceiving  is  dramatically  increased  if  intercourse  occurs  in  the  three  days   leading  up  to  and  including  ovulation.

When to have sex?

  • In  a  28-­‐day  cycle,  ovulation  typically  occurs  around  day  14  and  the  chance  of  conceiving  is   greatest  between  days  11  and  14.
  • In  longer  cycles,  say  35  days  between  periods,  ovulation  happens  around  day  21  and  days  18-­‐21   are  the  most  fertile  days.  In  a  24-­‐day  cycle  ovulation  happens  around  day  10  and  the  most  fertile   days  are  days  7  to  10.
  • If  a  woman  has  sex  six  or  more  days  before  she  ovulates,  the  chance  she  will  get  pregnant  is   virtually  zero.
  • If  she  has  sex  five  days  before  she  ovulates,  her  probability  of  pregnancy  is  about  5%.    Her   probability  of  pregnancy  rises  steadily  until  the  two  days  before  ovulation.
  • If  she  has  sex  on  either  of  these  two  days,  she  has  a  25-­‐30%  chance  of  becoming  pregnant.
  • After  this,  the  probability  of  pregnancy  declines  rapidly  and  by  12-­‐24  hours  after  she  ovulates,  a   woman  is  no  longer  able  to  get  pregnant  during  that  cycle.

Be aware of physical changes too

  •  A  few  days  before  ovulation  the  vaginal  mucus  changes  and  becomes  clear  and  slippery;  the   consistency  of  egg  white.    Mucus  changes  provide  an  early  and  useful  cue  that  ovulation  is   approaching.  Fertility  awareness,  the  ability  to  recognise  the  physical  changes  that  occur  before   ovulation,  can  help  couples  achieve  pregnancy.