Timing is Everything: How to Plan Insemination Around Your Cycle

For many people starting their fertility journey, home insemination is a low-cost, non-invasive first step to becoming a parent.  This method involves placing sperm samples into the vagina using a syringe and can be done privately at home.

Before performing home insemination, it’s helpful to understand a few key biological facts:

• Sperm can live up to 5 days inside a woman’s body when fertile-quality cervical mucus is present.
• An egg can only live up to 24 hours after ovulation

So, it is very important to time insemination correctly, to ensure sperm is present when the egg is released.

In this blog, we will walk through how to identify when you are ovulating by learning simple signs your body gives you, so you can maximize the chance of conception during home insemination.

The Four Hormones of the Menstrual Cycle

Let’s start with hormones that play a role in the women’s cycle. There are four of them.

1. Follicle-Stimulating hormone (FSH): released by the brain, this hormone stimulates immature eggs in the ovaries to grow.
2. Estrogen: Produced by the growing follicle, estrogen rises and signals the brain to release luteinizing hormone.
3. Luteinizing hormone (LH): Triggers ovulation – the release of a mature egg from the follicle.
4. Progesterone: Released from the empty follicle after ovulation, progesterone supports the uterine lining in preparation for possible implantation.

Types of Cervical Mucus

Now, let’s look at different types of cervical mucus. Cervical mucus changes sensation throughout a woman’s cycle due to hormonal fluctuation.

1. G-type mucus (Gastagenic)

Hormone influence: Progesterone (after ovulation)

Texture/sensation: Thick, dense, sticky, or dry

Function: Creates a barrier to sperm — forms a “mucus plug” that protects the uterus from bacteria and sperm during non-fertile times. It does inhibit sperm passage and has antimicrobial properties.

Microscopic Patterns: Under the microscope, cervical mucus forms dot patterns.

2. EL (Estrogenic- Loaves)

Hormone influence: Estrogen (approaching ovulation)

Texture/sensation: Moist, slightly sticky

Function: Begins to support sperm movement, but can still filter out abnormal sperm

 Microscopic pattern: Under the microscope, cervical mucus forms ferning or crystallization patterns.

3. ES (Estrogenic- Sperm transmission)

Hormone influence: High estrogen (peak fertility)

Texture/sensation: Stretchy, slippery, clear — often compared to raw egg whites

Function: Helps sperm survive and travel through the cervix toward the egg; indicates peak fertility

Microscopic Pattern: Under the microscope, cervical mucus forms stripe patterns. Sperm can pass through this pattern and swim towards the egg.

Understanding Your Cycle

A typical cycle ranges from 24-36 days and can be divided into three phases.

Pre-Ovulatory Phase

Begins on the first day of menses. Progesterone and estrogen levels are low, and the uterus is shedding. FSH stimulates follicles in the ovaries to grow. The cervix produces thick, dry, unchanging G-type mucus.

Starts on the first day of menses and ends on the last day of G mucus.

Ovulatory Phase

Growing follicles produce estrogen, leading to moist mucus. Ovulation occurs- the egg is released. This is the fertile time in your cycle.

Starts on the first day of EL or ES mucus and ends three days after the last day of ES mucus.

Post-Ovulatory Phase

After ovulation, progesterone rises to keep the uterine lining for a potential pregnancy. If pregnancy does not occur, hormone levels drop, and the cycle restarts with menstruation.

Identifying Your Fertile Window

Fertile window refers to a few days in a woman’s cycle where pregnancy is possible, including the ovulatory phase.  So, this is when insemination is most likely to lead to pregnancy.

• The ovulatory phase starts with the first appearance of EL or ES mucus and lasts until three days after the last observation of ES mucus.
• Research suggests ovulation is most likely to occur within three days before or after the last day of ES mucus.

To pinpoint ovulation more accurately, you can track your LH surge – a rapid increase in LH that occurs 24-36 hours before ovulation. You can detect this surge using over-the-counter LH test strips, which are similar to pregnancy tests. They are easily found online.

Tip: Start LH testing on the first day you notice EL or ES-type cervical mucus.

By learning how to recognize your body’s signals – from cervical mucus to hormonal surges- you will be better prepared to choose the right time for home insemination.

This blog is for educational purposes only and is not intended for medical advice. If you have questions or concerns, please consult with your healthcare provider.

Written by Shiho Yoshida

Shiho is a Biological Analyst at Seattle Sperm Bank, where she is responsible for the cryopreservation process and preparing vials. She holds a Bachelor of Science in Molecular, Cellular, and Developmental Biology from the University of Washington. She is also certified as a women’s health and fertility educator through FEMM Health. You can reach out to her at shiho@seattlespermbank.com.