IVF segmentation - separating collection cycles and transfer cycles

Segmentation in IVF is when the egg collection and embryo transfer occur in two separate cycles. This enables you to recover between the initial cycle of treatment and the implantation of the embryos.

You will firstly have a round of Mild IVF. This will involve 5-9 days of medication and regular scans/blood tests before you undergo egg collection. The eggs will then be fertilised and any resulting embryos will be frozen. When you are ready for the embryos to be put back, you will come back to the clinic for a Natural cycle with no stimulating drugs. You will be monitored closely and given medication to make your uterus receptive for implantation before you have the embryo transfer.

How is Segmented IVF different?

In conventional IVF, the woman’s cycle is shut down into effectively into a temporary menopausal state before she is given higher dose stimulating drugs to ripen multiple eggs. In this method, daily injections are given for 3-4 weeks.  Up to a maximum of three embryos (between 1-3) resulting from egg collection and fertilisation are then put back into the womb within the same cycle, while any spare embryos suitable for freezing are frozen. Mild IVF on the other hand only includes 5-9 days of low-dose stimulating drugs in a woman’s natural cycle without making her menopausal. In segmentation of mild IVF cycle, the embryos are put back in a separate Natural cycle.

What are the benefits of segmentation? 

  • Improved uterine environment: Following high dose stimulation treatment, the uterine environment is not the healthiest environment for implantation of the embryo. It has indeed been found that the womb lining can be less favourable to implantation after high stimulation, which can result in very high levels of oestrogen in the blood. There are many additional factors such as immunological disruption, an unfavourable oestrogen: progesterone ratio, changes in blood flow, hormones and chemicals which can result from a high stimulation cycle, all of which can adversely affect the chance of implantation. By minimising stimulation and putting embryos back in a separate natural cycle, the environment of the uterus is more favourable for implantation.
  • A stronger chance of embryo implantation: The uterine environment factors mentioned above are all important when it comes to the embryo implanting and developing in the womb. Transferring embryos into a healthy drug-free womb after a Natural cycle means that you are giving them the best possible chance of implantation.
  • Fewer side effects: The side effects of conventional treatment can be unpleasant and potentially dangerous. For example, Ovarian Hyperstimulation Syndrome (OHSS) is a medical condition caused by over stimulation of the ovaries. OHSS is an uncomfortable and potentially fatal condition, which can be exacerbated by hCG, a hormone used as a trigger in conventional IVF treatment. Mild IVF treatment uses low doses of stimulation for a shorter period of time and a GnRH agonist rather than hCG as a trigger, both of which can effectively eradicate the risk of severe OHSS and hospital admission.
  • Less stressful IVF: The treatment protocol with Mild IVF is around 2 weeks long, in contrast to 4-5 weeks of treatment with conventional IVF. The use of fewer drugs means fewer injections, less time in clinic, fewer blood tests and a less stressful treatment process. By separating the egg collection and embryo transfer we are giving you a chance to recover and recoup before coming back for the completion of treatment.
  • Better health for the baby: Research has shown that babies born after transfer in a Natural cycle have a statistically significant higher birth weight than babies conceived from embryos transferred within a conventional stimulated cycle. A baby’s birth weight has a long-term impact on future health and development.

For more information, see our FAQs about IVF.

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Dr Ippokratis Sarris
Lead Consultant St Paul's

Dr Ippokratis Sarris

MA(Cantab) BMBCh(Oxon) DFSRH MRCOG DM Dr Ippokratis Sarris  is a Consultant in Gynaecology, Reproductive Medicine and Surgery. He graduated from Trinity College, Cambridge, in 1999 an....