At Pacific Fertility Center we aim to help our patients build a healthy family. To build healthy families, maximum pregnancy rates are a goal, but maximum pregnancy rates must be balanced by consideration of risk, the chance of an adverse outcome. High pregnancy rates with minimal risk is PFC’s goal.

The risk of multiple pregnancy has increased as fertility therapy has improved. The wider use of gonadotropins in the 1990s to induce ovulation of multiple follicles, as well as the use of more effective laboratory and clinical IVF methods, resulted in production of more and healthier oocytes and more embryos, and increased the chances of multiple pregnancy. The very dramatic improvement in success rates over this time period resulted in many more children being delivered after fertility therapies, but also more twins, triplets, and higher order multiples.

Over the last twenty years, the incidence of multiple birth has increased nationally. According to the National Vital Statistics Report and the March of Dimes, the incidence of twins has increased by two-thirds, and the number of triplets and quadruplets has increased four-fold since 1980.

It is thought that about one-third of multiple pregnancies arise because women are waiting until later in life to conceive; age is a well-known risk factor for multiples. Another third arise from use of ovulation induction with gonadotropins (Pergonal, Follistim, Gonal-F, Repronex) alone. Less than one fifth of multiples are from assisted reproduction techniques (IVF and related procedures). Assisted reproduction in 2003 accounted for 18% of multiple pregnancies, 16% of twins and 44% of triplets ¹.

The risks to the children of multiple pregnancy are numerous. Low birth weight and very low birth weight are increased in children born as multiples. The chance of low birth weight (<2500g) is increased 8 times in twins. Cerebral palsy is increased 4 times, neonatal death risk by 7 times ^{2, 3}.

The risk to the mother from multiple pregnancy is also increased. Pre-eclampsia, high blood pressure, preterm labor, and premature rupture of membranes are all more common with multiple pregnancy ⁴ .

Multiple pregnancy is also expensive. It is estimated that twins alone cost the healthcare system some $600,000,000. There is clear evidence of an increase in parenting stress and divorce in families of multiples ^{5, 6} .

The need to assure our patients of the highest quality care requires that we bear this in mind – the healthiest pregnancy is a singleton pregnancy.

Pregnancy requires the cooperation of sperm and egg, accurate transcription of the early genetic code in the developing embryo, a fertile spot for attachment to the mother in the uterus, and a route for getting there. All other factors being equal, pregnancy rates almost double when two embryos are transferred instead of one, and increase again when a third and fourth embryo are added. The desire for high pregnancy rates has driven a desire for more embryos to be transferred ⁷ .

Improvements in insemination technique, embryo culture methods, and transfer efficiency have added substantially to pregnancy rates. Each embryo transferred today has a considerably higher chance of producing a pregnancy than an embryo transferred twenty years ago. Such improvements have enabled us to think about ways to reduce the risk of multiple pregnancy by transferring fewer embryos.

The development of blastocyst (day 5 embryo) culture techniques allows the selection of high quality embryos for transfer. The blastocyst stage requires advanced incubation techniques with low oxygen incubators and specialized culture media. A tight quality control system is also required. The blastocyst stage is a more advanced stage in which the genetic code of the embryo is fully activated and working. Only the healthiest of embryos can move to the more advanced stages, allowing selection of the best embryos for transfer.

In 2006 the ASRM published guidelines for number of embryos to transfer:

These guidelines encourage all of us to transfer ‘just enough’ embryos to achieve pregnancy.

Pacific Fertility Center has pioneered techniques of transferring fewer embryos. Last year, in 2007, our program of single embryo transfer in oocyte donation recipients produced a 66% pregnancy rate. The multiple pregnancy rate in this group was minimal. Utilizing a single embryo, two-thirds of patients were able to conceive a singleton pregnancy. This pregnancy rate was very similar to the overall pregnancy rates regardless of the number of embryos transferred.

Today half of our patients using oocyte donation elect to transfer a single embryo. Single embryo transfer is not always possible. Our criteria include age and embryo quality. A young woman (under age 35) with high quality blastocyst stage embryos and a healthy uterus can reliably transfer a single embryo and achieve high pregnancy rates. An older woman (over 40) may need to transfer 3 or more embryos to achieve a good pregnancy rate. Because of the higher number of embryos transferred, the risk of multiple pregnancy remains higher in these older age groups⁹ .

Pacific Fertility Center is very pleased to offer these techniques of single embryo transfer as some of the best and most advanced fertility treatment technology available. We are moving closer to our goal of growing families, one healthy baby at a time.   Philip Chenette, MD

1. Martin, Births: Final Data for 2003. National Vital Statistics Reports, volume 54, number 2, 2005
2. Scher, Ped Res, Vol. 52:671-81, 2002
3. Rutter, J Child Psychol Psych, Vol. 44:326-41, 2003
4. Pinborg, Human Reproduction, Vol. 18:1234-43, 2003
5. Griesinger, Hum Reproduction, Vol. 19:1239-1241, 2004
6. Glazebrook, Fertil Steril, Vol. 81:505-11, 2004
7. Paulson RJ, Fertil Steril., Vol. 53:870-874 , 1990
8. Fertil Steril, Vol. 85, Suppl. 4, 2006
9. Pacific Fertility Center 2007 IVF Statistics

Each year physicians and staff of Pacific Fertility Center attend the annual conference of the American Society for Reproductive Medicine (ASRM), a non-profit member-based organization established for the advancement of reproductive medicine. This gathering draws thousands of professionals from around the world to share advances in the field. Over 1600 abstracts were submitted for inclusion in the 2004 program. Our physicians Drs. Schriock and Chenette, and Lab Director Joe Conaghan have summarized a few topics here, based on the research’s relevance to clinical practice.

Same Success for Single Embryo Transfer
Some countries have mandated single embryo transfers (SET) in order to reduce the high rate of multiple-births from IVF treatment. Sweden’s rule was set into place January 1, 2003. A retrospective study has examined 1664 fresh IVF/ICSI/ET cycles before, during and after the transition to the new policy. Patients were of similar maternal age (mean 33.3-33.4), similar demographic characteristics and embryo quality scores.

The study revealed no difference in overall clinical pregnancy rate (33.3%, 32.8%, 33.8%) among those women studied. (Note that their mean age is less than the average age of PFC’s patients. Age is a key factor in the success or failure of IVF.) But the rate of twinning drastically reduced as a result of the new law prohibiting more than one embryo transfer (8.8% vs. 22.6% prior, and 16.3% during transition to the new policy). Sweden’s new policy appears to be resulting in a significant reduction of multiple births in young patients, while not impacting the overall clinical pregnancy rate.

Obesity Reduces Pregnancy Outcome
An extensive study has revealed that patients with a high body mass index (BMI), the method of measuring normal weight range, face a significant obstacle to getting pregnant. Specifically, researchers at the Beth Israel Deaconess Medical Center in Boston identified a 60% reduction in pregnancy rates in those with high BMI, or very obese, compared to those with a moderate to low BMI.

Researchers analyzed the records of 6,827 fresh non-donor cycles in which patients’ BMI had been recorded. The group was divided into five different weight categories, the maximum being a BMI 35 -39 kg/m2- considered obese. Researchers found no significant difference among participants with respect to the number of mature follicles observed, oocytes retrieved, mature oocytes produced, cycle number per patient and number of embryos transferred. However, they noticed significantly lower implantation rates and clinical pregnancy rates in those with a BMI >35 kg/m2 compared to all other BMI groups.

Progesterone Supplementation Not Needed
A group of researchers at the Carolinas Medical Center in Charlotte examined two groups of IVF patients to determine significant difference in pregnancy rates between those who continued progesterone supplements into the 12th week of pregnancy vs. those who had not. 237 patients categorized as the “long group” received 25mg intramuscular dose of progesterone the day of retrieval followed by a daily dose of 50mg IM until the pregnancy test and then daily through the first trimester. Another group of 121 patients, the “short group” continued same dose progesterone but only until the pregnancy test.

The study revealed similar conception rates for both groups. There was no significant difference in delivery rates when comparing all patients with a positive pregnancy test. However, both groups showed a similar degree of pregnancy loss, but at different times. Researchers concluded that long progesterone supplementation may support early pregnancy development through viability at 7 weeks but does not improve overall survival through the first trimester, showing more of a trend of delaying, not preventing miscarriage. For this reason, progesterone support of early pregnancy does not appear to be justified.

FDA Changes Ahead
Starting in May 2004, the Food and Drug Administration will be taking an active role in overseeing all aspects of health and safety of IVF clinical laboratory procedures, which are currently regulated by states. The changes are expected to increase the number of, and frequency of tests that patients will be required to undergo. Fertility Flash will publish a more extensive summary of this topic and how it will impact rates/procedures at PFC in one of our Spring 2005 issues. If you have any questions in the meantime, feel free to email us.

Drs. Chenette and Schriock attended the 2004 ASRM convention along with Lab Director Joe Conaghan and other PFC staff members. PFC’s medical team is continually evaluating the latest research. Our patients’ welfare is PFC’s first priority. With this in mind, be assured we do not include new technologies and treatments unless they are backed with solid, evidenced-based research.

Each year physicians and staff of Pacific Fertility Center attend the annual conference of the American Society for Reproductive Medicine (ASRM), a non-profit member-based organization established for the advancement of reproductive medicine. This gathering draws thousands of professionals from around the world to share advances in the field. Over 1600 abstracts were submitted for inclusion in the 2004 program. Our physicians Drs. Schriock and Chenette, and Lab Director Joe Conaghan have summarized a few topics here, based on the research’s relevance to clinical practice.Same Success for Single Embryo Transfer
Some countries have mandated single embryo transfers (SET) in order to reduce the high rate of multiple-births from IVF treatment. Sweden’s rule was set into place January 1, 2003. A retrospective study has examined 1664 fresh IVF/ICSI/ET cycles before, during and after the transition to the new policy. Patients were of similar maternal age (mean 33.3-33.4), similar demographic characteristics and embryo quality scores.

The study revealed no difference in overall clinical pregnancy rate (33.3%, 32.8%, 33.8%) among those women studied. (Note that their mean age is less than the average age of PFC’s patients. Age is a key factor in the success or failure of IVF.) But the rate of twinning drastically reduced as a result of the new law prohibiting more than one embryo transfer (8.8% vs. 22.6% prior, and 16.3% during transition to the new policy). Sweden’s new policy appears to be resulting in a significant reduction of multiple births in young patients, while not impacting the overall clinical pregnancy rate.

Obesity Reduces Pregnancy Outcome
An extensive study has revealed that patients with a high body mass index (BMI), the method of measuring normal weight range, face a significant obstacle to getting pregnant. Specifically, researchers at the Beth Israel Deaconess Medical Center in Boston identified a 60% reduction in pregnancy rates in those with high BMI, or very obese, compared to those with a moderate to low BMI.

Researchers analyzed the records of 6,827 fresh non-donor cycles in which patients’ BMI had been recorded. The group was divided into five different weight categories, the maximum being a BMI 35 -39 kg/m2- considered obese. Researchers found no significant difference among participants with respect to the number of mature follicles observed, oocytes retrieved, mature oocytes produced, cycle number per patient and number of embryos transferred. However, they noticed significantly lower implantation rates and clinical pregnancy rates in those with a BMI >35 kg/m2 compared to all other BMI groups.

Progesterone Supplementation Not Needed
A group of researchers at the Carolinas Medical Center in Charlotte examined two groups of IVF patients to determine significant difference in pregnancy rates between those who continued progesterone supplements into the 12th week of pregnancy vs. those who had not. 237 patients categorized as the “long group” received 25mg intramuscular dose of progesterone the day of retrieval followed by a daily dose of 50mg IM until the pregnancy test and then daily through the first trimester. Another group of 121 patients, the “short group” continued same dose progesterone but only until the pregnancy test.

The study revealed similar conception rates for both groups. There was no significant difference in delivery rates when comparing all patients with a positive pregnancy test. However, both groups showed a similar degree of pregnancy loss, but at different times. Researchers concluded that long progesterone supplementation may support early pregnancy development through viability at 7 weeks but does not improve overall survival through the first trimester, showing more of a trend of delaying, not preventing miscarriage. For this reason, progesterone support of early pregnancy does not appear to be justified.

FDA Changes Ahead
Starting in May 2004, the Food and Drug Administration will be taking an active role in overseeing all aspects of health and safety of IVF clinical laboratory procedures, which are currently regulated by states. The changes are expected to increase the number of, and frequency of tests that patients will be required to undergo. Fertility Flash will publish a more extensive summary of this topic and how it will impact rates/procedures at PFC in one of our Spring 2005 issues. If you have any questions in the meantime, feel free to email us.

Drs. Chenette and Schriock attended the 2004 ASRM convention along with Lab Director Joe Conaghan and other PFC staff members. PFC’s medical team is continually evaluating the latest research. Our patients’ welfare is PFC’s first priority. With this in mind, be assured we do not include new technologies and treatments unless they are backed with solid, evidenced-based research.


Each year physicians and staff of Pacific Fertility Center attend the annual conference of the American Society for Reproductive Medicine (ASRM), a non-profit member-based organization established for the advancement of reproductive medicine. This gathering draws thousands of professionals from around the world to share advances in the field. Over 1600 abstracts were submitted for inclusion in the 2004 program. Our physicians Drs. Schriock and Chenette, and Lab Director Joe Conaghan have summarized a few topics here, based on the research’s relevance to clinical practice.Same Success for Single Embryo Transfer
Some countries have mandated single embryo transfers (SET) in order to reduce the high rate of multiple-births from IVF treatment. Sweden’s rule was set into place January 1, 2003. A retrospective study has examined 1664 fresh IVF/ICSI/ET cycles before, during and after the transition to the new policy. Patients were of similar maternal age (mean 33.3-33.4), similar demographic characteristics and embryo quality scores.

The study revealed no difference in overall clinical pregnancy rate (33.3%, 32.8%, 33.8%) among those women studied. (Note that their mean age is less than the average age of PFC’s patients. Age is a key factor in the success or failure of IVF.) But the rate of twinning drastically reduced as a result of the new law prohibiting more than one embryo transfer (8.8% vs. 22.6% prior, and 16.3% during transition to the new policy). Sweden’s new policy appears to be resulting in a significant reduction of multiple births in young patients, while not impacting the overall clinical pregnancy rate.

Obesity Reduces Pregnancy Outcome
An extensive study has revealed that patients with a high body mass index (BMI), the method of measuring normal weight range, face a significant obstacle to getting pregnant. Specifically, researchers at the Beth Israel Deaconess Medical Center in Boston identified a 60% reduction in pregnancy rates in those with high BMI, or very obese, compared to those with a moderate to low BMI.

Researchers analyzed the records of 6,827 fresh non-donor cycles in which patients’ BMI had been recorded. The group was divided into five different weight categories, the maximum being a BMI 35 -39 kg/m2- considered obese. Researchers found no significant difference among participants with respect to the number of mature follicles observed, oocytes retrieved, mature oocytes produced, cycle number per patient and number of embryos transferred. However, they noticed significantly lower implantation rates and clinical pregnancy rates in those with a BMI >35 kg/m2 compared to all other BMI groups.

Progesterone Supplementation Not Needed
A group of researchers at the Carolinas Medical Center in Charlotte examined two groups of IVF patients to determine significant difference in pregnancy rates between those who continued progesterone supplements into the 12th week of pregnancy vs. those who had not. 237 patients categorized as the “long group” received 25mg intramuscular dose of progesterone the day of retrieval followed by a daily dose of 50mg IM until the pregnancy test and then daily through the first trimester. Another group of 121 patients, the “short group” continued same dose progesterone but only until the pregnancy test.

The study revealed similar conception rates for both groups. There was no significant difference in delivery rates when comparing all patients with a positive pregnancy test. However, both groups showed a similar degree of pregnancy loss, but at different times. Researchers concluded that long progesterone supplementation may support early pregnancy development through viability at 7 weeks but does not improve overall survival through the first trimester, showing more of a trend of delaying, not preventing miscarriage. For this reason, progesterone support of early pregnancy does not appear to be justified.

FDA Changes Ahead
Starting in May 2004, the Food and Drug Administration will be taking an active role in overseeing all aspects of health and safety of IVF clinical laboratory procedures, which are currently regulated by states. The changes are expected to increase the number of, and frequency of tests that patients will be required to undergo. Fertility Flash will publish a more extensive summary of this topic and how it will impact rates/procedures at PFC in one of our Spring 2005 issues. If you have any questions in the meantime, feel free to email us.

Drs. Chenette and Schriock attended the 2004 ASRM convention along with Lab Director Joe Conaghan and other PFC staff members. PFC’s medical team is continually evaluating the latest research. Our patients’ welfare is PFC’s first priority. With this in mind, be assured we do not include new technologies and treatments unless they are backed with solid, evidenced-based research.