the field of assisted reproductive technology ( art ) is advancing day by day with newer laboratory techniques being discovered .
the area of cryopreservation is one of them . till date , it has been possible to freeze sperms and embryos for many years , but successful pregnancies from oocytes have been elusive with only few hundred live births worldwide .
oocyte cryopreservation has gained more attention in art , especially because synchronization between recipient and donor need not be compulsory in the donor oocyte programme , other indications being pre - chemotherapy preservation of fertility , premature ovarian failure , and postponement of childbearing function .
the success rates in oocyte cryopreservation have been cited as low and are debatable , with literature review of 21 studies in peer - reviewed journals revealing a mean survival rate of 47% , fertilization rate of 52.5% and mean pregnancy rate / thawed oocyte being 1.521.8% .
the patient was a 29 year old , with a previous bad obstetric history and an abnormal karyotype ( 46xx , t[3:9 ] [ p21.3;p24 ] , t [ 7:10 ] [ p22;q22.1 ] ) , which necessitated the use of donor oocytes for the present conception .
the reason for the use of frozen oocytes sourced from egg - sharing and egg - donation patients was the non - availability of compatible fresh donors and insistence of the couple to continue the treatment cycle .
the couple was then counseled about the use of frozen  thawed oocytes and the expected low success rate for this cycle after obtaining informed consent .
freezing was initiated 12 h post - retrieval , after denuding the cumulus with hyaluronidase and confirming metaphase - ii maturity status .
cook 's oocyte freezing media ( cook medical , queensland , australia ) was used after warming the required quantity to room temperature , the active cryoprotectants being propanediol in increasing concentrations from 0.75 to 1.5 mol / l ( solutions 1 and 2  for 7min and 30 s , respectively ) and then transferred to solution 3 containing 1.5 mol / l propanediol and 0.2 mol / l sucrose [ figure 1 ] for 5 min .
the oocytes were loaded into pre - labeled straws ( cryo - bio systems , rocket medical plc , washington , england ) , plugged and placed into the cryochamber ( planer kryo 360 , planer products ltd , burnsville , usa ) .
the initial chamber temperature at + 20c was slowly cooled to 8c at the rate of 2c / min .
seeding was manually performed at 8c . after a hold time of 10min at 8c , the straws were cooled slowly to 30c at a rate of 0.3c / min and then rapidly to 150c at a rate of 50c / min . after 10 min of stabilization ,
the oocytes were subjected to cryopreservation for 6 months . because a suitable fresh donor was unavailable for this particular patient , we were able to use the cryopreserved oocytes for this couple .
the endometrium was prepared with incremental doses of estrogen ( estradiol valerate 2 mg ; german remedies , mumbai , india ) commencing from day 2 or day 3 of the cycle to a maximum of 8mg / day with initiation of micronised progesterone 400 mg thrice a day , from the day before thawing .
the optimum endometrium for transfer was considered to be 10 mm , which was observed in mid - cycle .
we decided to thaw at least 10 oocytes in order to enhance the chances of achieving enough good - grade embryos for transfer , success having evaded us earlier .
for the thawing process , the straws containing the oocytes were removed from the liquid nitrogen , air dried for 30s , and then immersed in a water bath at 30c for 40s .
the oocytes were first passed through solutions 12 containing cryobuffer supplemented with decreasing concentration of propanediol ( 1.00.5mol / l ) and increasing concentration of sucrose ( 0.20.3mol / l ) for 5 min at room temperature , respectively .
the oocytes were then transferred to solution 3 ( 0.3 mol / l sucrose ) for 10 min at room temperature followed by 37c on a warmer plate .
a survival check carried out under the inverted microscope revealed eight oocytes that survived the thawing process [ figure 2 ] .
oocytes with intact zona , clear perivitelline space , and visible polar body were considered as normal and were further cultured in the cleavage media ( quinn 's , sage in vitro fertilization , trumbull ct , usa ) at 37c and 5% co2 for 2 h before injection .
subsequently , the oocytes were injected with frozen  thawed and prepared sample of husband 's sperms .
intracytoplasmic sperm injection [ figures 3 and 4][49 ] was the preferred method for fertilization , owing to an expected zona hardening following oocyte cryopreservation .
the injected oocytes were further cultured in cleavage media in a trigas incubator until pronucleus check 1618h later .
iii ) [ figures 5 and 6 ] were observed and transferred on day 2 using a labotect catheter ( labotect gmbh , gottinggen , germany ) .
the assessment of embryo grading was performed as described by veeck l. why five and not the recommended three embryos ?
well , considering our previous experience of inadequate embryos for transfer following thawing and negative result for pregnancy , we decided to transfer at least five of this crop , which , as we mentioned , did not have the conventional cleavage or grade as expected ( i.e. , four cells , grade i 
once the serum -hcg was positive , an ultrasound on the 38 day revealed a single intrauterine gestational sac .
since then she progressed uneventfully , with early fetal screening tests being normal until the 5 month , when she was diagnosed with mild pregnancy - induced hypertension and was treated with anti - hypertensives . during her level-2 scan at 22 weeks , where the fetal screening was normal
, a shortened cervix of 1.5 cm was imaged , suggestive of cervical incompetence . since then , she was admitted with us for careful surveillance of both the mother and the baby .
she did moderate physical activities and her blood pressure was well controlled with anti - hypertensives .
she delivered a healthy male baby weighing 2.54 kg [ figure 7 ] . both the mother and the baby were discharged uneventfully .
a general follow - up at 3 months showed normal development for age [ figure 8 ] .
we started oocyte freezing in the month of november 2005 and since then have frozen more than 100 oocytes [ table 1 ] .
the only media available were the irvine scientific vitrification media and cook media and there was a learning curve to be able to successfully freeze and retrieve oocytes .
however , in the initial phase of vitrification with irvine scientific media , close to 10 oocytes of different patient were frozen at the germinal vesicle and metaphase i , with three maturing to metaphase ii in in vitro maturation , but no fertilization .
subsequent reports of series of pregnancies and live births have confirmed that mature oocyte cryopreservation is now a viable option in appropriate circumstances .
other recent reports show that several babies have been born using oocyte cryopreservation and similar freezing and thawing procedures ( slow freezing and rapid thawing ) .
there is still ongoing research with regard to the optimum media and preference of freezing techniques like slow freeze or vitrification , the latter showing promising results . in our experience , the slow freeze method seemed to offer better retrieval rates ( 74% ) and fertilization rates ( 62% ) , although vitrification , according to the literature review , seems to offer comparable or even better clinical outcomes .
oocyte freezing can be welcomed as an emerging and useful technique , especially in donor programmes and in young women with cancer for fertility preservation options .
worldwide , there have been only few hundred babies born through this technique owing to the sensitive morphology and cryokinetics of the oocyte .
while we still conduct comparative research between the two freezing methods , namely slow freezing and vitrification , this little bundle of joy signals yet another landmark achievement for our country while serving as a ray of hope to many young women in need of oocyte freezing technology .
 we report the first pregnancy and birth in india after the transfer of embryos generated from frozen thawed oocytes . a 29-year - old woman with previous bad obstetric history and an abnormal karyotype , necessitating donor oocyte programme . 
 embryos were generated by microinjection of frozen  thawed sperms into thawed human oocytes ( intracytoplasmic sperm injection ) . 
 this resulted in an healthy male baby with a birth weight of 2.54 kg which was born by cesarean section at 3536 weeks of gestation with normal follow - up . 
 thus oocyte cryopreservation can be performed with reproducible success leading to a viable offspring . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION