Combined ovarian tissue cryopreservation and in vitro maturation of ovarian- tissue oocytes (OTO-IVM) for emergency fertility preservation in the early postpartum period: a case report and systematic review of the literature

When a young woman is diagnosed with cancer, the urgency to begin life-saving treatment often clashes with the desire to preserve her future ability to have children. Chemotherapy and radiation can damage the ovaries, potentially ending a woman's reproductive life before it has truly begun. For years, doctors have relied on a standard method to protect fertility: stimulating the ovaries with hormones to produce many mature eggs, which are then collected and frozen. However, this process takes weeks, a luxury that many patients do not have. In these emergency situations, doctors have turned to two alternative strategies. One involves freezing pieces of the ovarian tissue itself, which contains thousands of immature eggs waiting to develop. The other involves taking those immature eggs and helping them mature in a laboratory dish, a process known as in vitro maturation. While these methods offer hope, they are complex and their success depends heavily on the biological state of the patient's body at the time of collection.

This story centers on a specific, uncharted moment in a woman's life: the immediate weeks after giving birth. During this period, a woman's body is in a unique hormonal state. If she is breastfeeding, her body produces high levels of a hormone called prolactin, which naturally suppresses the signals that usually trigger ovulation. This creates a biological environment that is very different from the standard cycles doctors are used to studying. A team of researchers at Tel Aviv Sourasky Medical Center recently attempted to apply these emergency fertility preservation techniques to a woman in this exact situation. Their goal was to see if the ovaries of a lactating mother, just three weeks after a cesarean section, could still provide viable eggs for future use when faced with the immediate need to start cancer treatment.

The patient was a twenty-three-year-old woman who had given birth three weeks prior and was actively breastfeeding. Shortly after delivery, she was diagnosed with a rare and aggressive form of cancer called Ewing sarcoma, which had spread to her pelvis and lungs. The treatment required was a powerful chemotherapy regimen that would almost certainly destroy her ovarian function. Because she needed to start treatment immediately, there was no time for the standard weeks-long hormone stimulation. The medical team proposed a combined approach: they would remove one ovary to freeze the tissue for later use, while simultaneously trying to collect immature eggs from both ovaries to mature them in the lab. Before the procedure, the team confirmed her hormonal status; her prolactin levels were high, consistent with breastfeeding, and her ultrasound showed a healthy number of small follicles, the tiny sacs in the ovary that hold eggs.

The procedure began with a short, four-day course of hormone priming to encourage the follicles to grow, followed by a trigger shot to prepare them for release. The team then attempted to collect eggs through a needle guided by ultrasound, a standard technique used in fertility clinics. Despite the follicles growing to a size that typically indicates they are ready, the needle aspiration yielded nothing. Not a single egg was found inside the follicles that had been stimulated. Undeterred, the team proceeded with the second part of the plan. They took the ovary that had been surgically removed and carefully dissected the outer layer of tissue, known as the cortex, to find eggs that were still trapped inside. From this tissue, they managed to retrieve eleven clusters of cells containing immature eggs. However, the outcome here was also disappointing. Six of these clusters were already damaged, and the remaining five were stuck at a very early stage of development. When the scientists placed these five eggs in a special culture medium designed to help them mature over forty-eight hours, none of them succeeded. They remained stuck in their early state and could not be frozen or used.

The only successful part of this complex effort was the freezing of thirty-five small fragments of the ovarian tissue. This tissue, which was confirmed to be free of cancer cells, remains the patient's only preserved reproductive material for now. The researchers then looked at the broader medical literature to see if anyone else had tried this before. They reviewed dozens of studies involving similar techniques and hundreds of reports on fertility treatments after pregnancy. They found that while doctors had successfully frozen ovarian tissue during pregnancy or after delivery, and while they had successfully used laboratory maturation for women with cancer, no one had ever reported trying to mature eggs from a woman who was both immediately postpartum and actively breastfeeding.

The failure of the eggs to mature, despite the follicles growing normally, points to a specific biological hurdle. The researchers suggest that the unique hormonal environment of the early postpartum period, particularly the high levels of prolactin from breastfeeding, may have disrupted the final steps of egg development. It appears that while the body could build the "house" for the egg (the follicle), the "resident" (the egg itself) was not ready to move in or function correctly. This is distinct from the usual reasons eggs fail to mature, such as age or prior chemotherapy. The study also noted that the patient was taking several medications for pain and mental health, which could have influenced the results, but the pattern of failure suggests the postpartum state itself plays a significant role.

This case serves as a crucial warning and a guide for future medical decisions. It demonstrates that while freezing ovarian tissue is a robust and reliable backup plan that worked in this instance, relying on the collection and laboratory maturation of eggs in the immediate weeks after childbirth may be unreliable. The researchers emphasize that for women in this specific situation, doctors should manage expectations carefully. They should explain that the number of eggs seen on an ultrasound does not guarantee that mature eggs can be collected, especially when the mother is breastfeeding. The study concludes that while the technology is feasible to attempt, the biological reality of the early postpartum ovary may limit its success, and the frozen tissue remains the most durable option for preserving fertility in these urgent cases.