Timing for conception
When planning a baby, a couple needs to make sure that they are having regular sex. This also needs to happen at the correct time in the menstrual cycle.
Your fertility window
There is a certain time in the menstrual cycle when you are most fertile. This creates a 'fertility window' when it is possible for sex to result in conception. Being aware of when your fertility window is increases your chances of conception.
The reason for this is that sperm can survive for up to 5 days and the egg survives for only 12 to 24 hours. It helps to track your menstrual cycles and aim for sex at least every second day during this time.
If you have irregular cycles, we recommend you try to have sex every second to third day.
How to track your menstrual cycle
Tracking your menstrual cycle can help you work out when your fertility window is. You can simply mark your periods on a calendar or try one of the many apps available online.
Fertility apps — Healthify (external link)
Your menstrual cycle can range from 21 to 35 days with the average cycle 28 days. Ovulation usually happens 14 days before your period starts. It is a good idea to track 2 or 3 cycles and work out the average length of your cycle. From this you can work out the time you are most likely to ovulate.
- If your cycle is 28 days, ovulation should happen on day 14 — have regular sex from 10 days after your period started.
- If your period is 35 days, ovulation should happen on day 21 — have regular sex from 17 days after your period started.
Signs you are ovulating
There are things that change during your menstrual cycle that can help you to identify if you have ovulated.
Changes in your in cervical mucus
Just before ovulation your cervical mucus changes to become clear and slippery. This is to allow sperm to pass through the cervix. After ovulation, the mucus becomes thicker and changes to white or yellow. This makes it difficult for sperm to pass through.
Changes in your hormones
Measuring luteinising hormone (LH) can show when ovulation occurs. LH level increases 1 to 2 days before ovulation, and it can be measured in your wee. These tests are generally useful for the 5 to 6 days before your expected ovulation day. Commercial ovulation kits should be used with caution as there is limited evidence they improve fertility outcomes.
Changes in body temperature
Measuring your 'basal temperature' can help identify if you have ovulated. However this is not always recommended as it tells you when you have already ovulated, potentially missing your fertility window.
Fertility awareness | Ngā ratonga matahua — Sexual Wellbeing Aotearoa (external link)